hypothesis for research papers

How to Write a Hypothesis in 6 Steps, With Examples

A hypothesis is a statement that explains the predictions and reasoning of your research—an “educated guess” about how your scientific experiments will end. As a fundamental part of the scientific method, a good hypothesis is carefully written, but even the simplest ones can be difficult to put into words. 

Want to know how to write a hypothesis for your academic paper ? Below we explain the different types of hypotheses, what a good hypothesis requires, the steps to write your own, and plenty of examples.

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What is a hypothesis? 

One of our 10 essential words for university success , a hypothesis is one of the earliest stages of the scientific method. It’s essentially an educated guess—based on observations—of what the results of your experiment or research will be. 

Some hypothesis examples include:

• If I water plants daily they will grow faster.
• Adults can more accurately guess the temperature than children can. 
• Butterflies prefer white flowers to orange ones.

If you’ve noticed that watering your plants every day makes them grow faster, your hypothesis might be “plants grow better with regular watering.” From there, you can begin experiments to test your hypothesis; in this example, you might set aside two plants, water one but not the other, and then record the results to see the differences. 

The language of hypotheses always discusses variables , or the elements that you’re testing. Variables can be objects, events, concepts, etc.—whatever is observable. 

There are two types of variables: independent and dependent. Independent variables are the ones that you change for your experiment, whereas dependent variables are the ones that you can only observe. In the above example, our independent variable is how often we water the plants and the dependent variable is how well they grow. 

Hypotheses determine the direction and organization of your subsequent research methods, and that makes them a big part of writing a research paper . Ultimately the reader wants to know whether your hypothesis was proven true or false, so it must be written clearly in the introduction and/or abstract of your paper. 

7 examples of hypotheses

Depending on the nature of your research and what you expect to find, your hypothesis will fall into one or more of the seven main categories. Keep in mind that these categories are not exclusive, so the same hypothesis might qualify as several different types. 

1 Simple hypothesis

A simple hypothesis suggests only the relationship between two variables: one independent and one dependent. 

• If you stay up late, then you feel tired the next day. 
• Turning off your phone makes it charge faster. 

2 Complex hypothesis

A complex hypothesis suggests the relationship between more than two variables, for example, two independents and one dependent, or vice versa. 

• People who both (1) eat a lot of fatty foods and (2) have a family history of health problems are more likely to develop heart diseases. 
• Older people who live in rural areas are happier than younger people who live in rural areas. 

3 Null hypothesis

A null hypothesis, abbreviated as H 0 , suggests that there is no relationship between variables. 

• There is no difference in plant growth when using either bottled water or tap water. 
• Professional psychics do not win the lottery more than other people. 

4 Alternative hypothesis

An alternative hypothesis, abbreviated as H 1 or H A , is used in conjunction with a null hypothesis. It states the opposite of the null hypothesis, so that one and only one must be true. 

• Plants grow better with bottled water than tap water. 
• Professional psychics win the lottery more than other people. 

5 Logical hypothesis

A logical hypothesis suggests a relationship between variables without actual evidence. Claims are instead based on reasoning or deduction, but lack actual data.  

• An alien raised on Venus would have trouble breathing in Earth’s atmosphere. 
• Dinosaurs with sharp, pointed teeth were probably carnivores. 

6 Empirical hypothesis

An empirical hypothesis, also known as a “working hypothesis,” is one that is currently being tested. Unlike logical hypotheses, empirical hypotheses rely on concrete data. 

• Customers at restaurants will tip the same even if the wait staff’s base salary is raised. 
• Washing your hands every hour can reduce the frequency of illness. 

7 Statistical hypothesis

A statistical hypothesis is when you test only a sample of a population and then apply statistical evidence to the results to draw a conclusion about the entire population. Instead of testing everything , you test only a portion and generalize the rest based on preexisting data. 

• In humans, the birth-gender ratio of males to females is 1.05 to 1.00.  
• Approximately 2% of the world population has natural red hair. 

What makes a good hypothesis?

No matter what you’re testing, a good hypothesis is written according to the same guidelines. In particular, keep these five characteristics in mind: 

Cause and effect

Hypotheses always include a cause-and-effect relationship where one variable causes another to change (or not change if you’re using a null hypothesis). This can best be reflected as an if-then statement: If one variable occurs, then another variable changes. 

Testable prediction

Most hypotheses are designed to be tested (with the exception of logical hypotheses). Before committing to a hypothesis, make sure you’re actually able to conduct experiments on it. Choose a testable hypothesis with an independent variable that you have absolute control over. 

Independent and dependent variables

Define your variables in your hypothesis so your readers understand the big picture. You don’t have to specifically say which ones are independent and dependent variables, but you definitely want to mention them all. 

Candid language

Writing can easily get convoluted, so make sure your hypothesis remains as simple and clear as possible. Readers use your hypothesis as a contextual pillar to unify your entire paper, so there should be no confusion or ambiguity. If you’re unsure about your phrasing, try reading your hypothesis to a friend to see if they understand. 

Adherence to ethics

It’s not always about what you can test, but what you should test. Avoid hypotheses that require questionable or taboo experiments to keep ethics (and therefore, credibility) intact.

How to write a hypothesis in 6 steps

1 ask a question.

Curiosity has inspired some of history’s greatest scientific achievements, so a good place to start is to ask yourself questions about the world around you. Why are things the way they are? What causes the factors you see around you? If you can, choose a research topic that you’re interested in so your curiosity comes naturally. 

2 Conduct preliminary research

Next, collect some background information on your topic. How much background information you need depends on what you’re attempting. It could require reading several books, or it could be as simple as performing a web search for a quick answer. You don’t necessarily have to prove or disprove your hypothesis at this stage; rather, collect only what you need to prove or disprove it yourself. 

3 Define your variables

Once you have an idea of what your hypothesis will be, select which variables are independent and which are dependent. Remember that independent variables can only be factors that you have absolute control over, so consider the limits of your experiment before finalizing your hypothesis. 

4 Phrase it as an if-then statement

When writing a hypothesis, it helps to phrase it using an if-then format, such as, “ If I water a plant every day, then it will grow better.” This format can get tricky when dealing with multiple variables, but in general, it’s a reliable method for expressing the cause-and-effect relationship you’re testing. 

5  Collect data to support your hypothesis

A hypothesis is merely a means to an end. The priority of any scientific research is the conclusion. Once you have your hypothesis laid out and your variables chosen, you can then begin your experiments. Ideally, you’ll collect data to support your hypothesis, but don’t worry if your research ends up proving it wrong—that’s all part of the scientific method. 

6 Write with confidence

Last, you’ll want to record your findings in a research paper for others to see. This requires a bit of writing know-how, quite a different skill set than conducting experiments. 

That’s where Grammarly can be a major help; our writing suggestions point out not only grammar and spelling mistakes , but also new word choices and better phrasing. While you write, Grammarly automatically recommends optimal language and highlights areas where readers might get confused, ensuring that your hypothesis—and your final paper—are clear and polished.

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Step-by-Step Guide: How to Craft a Strong Research Hypothesis

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Table of Contents

A research hypothesis is a concise statement about the expected result of an experiment or project. In many ways, a research hypothesis represents the starting point for a scientific endeavor, as it establishes a tentative assumption that is eventually substantiated or falsified, ultimately improving our certainty about the subject investigated.   

To help you with this and ease the process, in this article, we discuss the purpose of research hypotheses and list the most essential qualities of a compelling hypothesis. Let’s find out!  

How to Craft a Research Hypothesis  

Crafting a research hypothesis begins with a comprehensive literature review to identify a knowledge gap in your field. Once you find a question or problem, come up with a possible answer or explanation, which becomes your hypothesis. Now think about the specific methods of experimentation that can prove or disprove the hypothesis, which ultimately lead to the results of the study.   

Enlisted below are some standard formats in which you can formulate a hypothesis¹ :  

• A hypothesis can use the if/then format when it seeks to explore the correlation between two variables in a study primarily.  

Example: If administered drug X, then patients will experience reduced fatigue from cancer treatment.  

• A hypothesis can adopt when X/then Y format when it primarily aims to expose a connection between two variables  

Example: When workers spend a significant portion of their waking hours in sedentary work , then they experience a greater frequency of digestive problems.  

• A hypothesis can also take the form of a direct statement.  

Example: Drug X and drug Y reduce the risk of cognitive decline through the same chemical pathways  

What are the Features of an Effective Hypothesis?  

Hypotheses in research need to satisfy specific criteria to be considered scientifically rigorous. Here are the most notable qualities of a strong hypothesis:  

• Testability: Ensure the hypothesis allows you to work towards observable and testable results.  
• Brevity and objectivity: Present your hypothesis as a brief statement and avoid wordiness.  
• Clarity and Relevance: The hypothesis should reflect a clear idea of what we know and what we expect to find out about a phenomenon and address the significant knowledge gap relevant to a field of study.   

Understanding Null and Alternative Hypotheses in Research  

There are two types of hypotheses used commonly in research that aid statistical analyses. These are known as the null hypothesis and the alternative hypothesis . A null hypothesis is a statement assumed to be factual in the initial phase of the study.   

For example, if a researcher is testing the efficacy of a new drug, then the null hypothesis will posit that the drug has no benefits compared to an inactive control or placebo . Suppose the data collected through a drug trial leads a researcher to reject the null hypothesis. In that case, it is considered to substantiate the alternative hypothesis in the above example, that the new drug provides benefits compared to the placebo.  

Let’s take a closer look at the null hypothesis and alternative hypothesis with two more examples:  

Null Hypothesis:  

The rate of decline in the number of species in habitat X in the last year is the same as in the last 100 years when controlled for all factors except the recent wildfires.  

In the next experiment, the researcher will experimentally reject this null hypothesis in order to confirm the following alternative hypothesis :  

The rate of decline in the number of species in habitat X in the last year is different from the rate of decline in the last 100 years when controlled for all factors other than the recent wildfires.  

In the pair of null and alternative hypotheses stated above, a statistical comparison of the rate of species decline over a century and the preceding year will help the research experimentally test the null hypothesis, helping to draw scientifically valid conclusions about two factors—wildfires and species decline.   

We also recommend that researchers pay attention to contextual echoes and connections when writing research hypotheses. Research hypotheses are often closely linked to the introduction ² , such as the context of the study, and can similarly influence the reader’s judgment of the relevance and validity of the research hypothesis.  

Seasoned experts, such as professionals at Elsevier Language Services, guide authors on how to best embed a hypothesis within an article so that it communicates relevance and credibility. Contact us if you want help in ensuring readers find your hypothesis robust and unbiased.  

References  

• Hypotheses – The University Writing Center. (n.d.). https://writingcenter.tamu.edu/writing-speaking-guides/hypotheses  
• Shaping the research question and hypothesis. (n.d.). Students. https://students.unimelb.edu.au/academic-skills/graduate-research-services/writing-thesis-sections-part-2/shaping-the-research-question-and-hypothesis  

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What is a Research Hypothesis: How to Write it, Types, and Examples

Any research begins with a research question and a research hypothesis . A research question alone may not suffice to design the experiment(s) needed to answer it. A hypothesis is central to the scientific method. But what is a hypothesis ? A hypothesis is a testable statement that proposes a possible explanation to a phenomenon, and it may include a prediction. Next, you may ask what is a research hypothesis ? Simply put, a research hypothesis is a prediction or educated guess about the relationship between the variables that you want to investigate.  

It is important to be thorough when developing your research hypothesis. Shortcomings in the framing of a hypothesis can affect the study design and the results. A better understanding of the research hypothesis definition and characteristics of a good hypothesis will make it easier for you to develop your own hypothesis for your research. Let’s dive in to know more about the types of research hypothesis , how to write a research hypothesis , and some research hypothesis examples .  

Table of Contents

What is a hypothesis ?  

A hypothesis is based on the existing body of knowledge in a study area. Framed before the data are collected, a hypothesis states the tentative relationship between independent and dependent variables, along with a prediction of the outcome.  

What is a research hypothesis ?  

Young researchers starting out their journey are usually brimming with questions like “ What is a hypothesis ?” “ What is a research hypothesis ?” “How can I write a good research hypothesis ?”   

A research hypothesis is a statement that proposes a possible explanation for an observable phenomenon or pattern. It guides the direction of a study and predicts the outcome of the investigation. A research hypothesis is testable, i.e., it can be supported or disproven through experimentation or observation.     

Characteristics of a good hypothesis  

Here are the characteristics of a good hypothesis :  

• Clearly formulated and free of language errors and ambiguity  
• Concise and not unnecessarily verbose  
• Has clearly defined variables  
• Testable and stated in a way that allows for it to be disproven  
• Can be tested using a research design that is feasible, ethical, and practical   
• Specific and relevant to the research problem  
• Rooted in a thorough literature search  
• Can generate new knowledge or understanding.  

How to create an effective research hypothesis  

A study begins with the formulation of a research question. A researcher then performs background research. This background information forms the basis for building a good research hypothesis . The researcher then performs experiments, collects, and analyzes the data, interprets the findings, and ultimately, determines if the findings support or negate the original hypothesis.  

Let’s look at each step for creating an effective, testable, and good research hypothesis :  

• Identify a research problem or question: Start by identifying a specific research problem.   
• Review the literature: Conduct an in-depth review of the existing literature related to the research problem to grasp the current knowledge and gaps in the field.   
• Formulate a clear and testable hypothesis : Based on the research question, use existing knowledge to form a clear and testable hypothesis . The hypothesis should state a predicted relationship between two or more variables that can be measured and manipulated. Improve the original draft till it is clear and meaningful.  
• State the null hypothesis: The null hypothesis is a statement that there is no relationship between the variables you are studying.   
• Define the population and sample: Clearly define the population you are studying and the sample you will be using for your research.  
• Select appropriate methods for testing the hypothesis: Select appropriate research methods, such as experiments, surveys, or observational studies, which will allow you to test your research hypothesis .  

Remember that creating a research hypothesis is an iterative process, i.e., you might have to revise it based on the data you collect. You may need to test and reject several hypotheses before answering the research problem.  

How to write a research hypothesis  

When you start writing a research hypothesis , you use an “if–then” statement format, which states the predicted relationship between two or more variables. Clearly identify the independent variables (the variables being changed) and the dependent variables (the variables being measured), as well as the population you are studying. Review and revise your hypothesis as needed.  

An example of a research hypothesis in this format is as follows:  

“ If [athletes] follow [cold water showers daily], then their [endurance] increases.”  

Population: athletes  

Independent variable: daily cold water showers  

Dependent variable: endurance  

You may have understood the characteristics of a good hypothesis . But note that a research hypothesis is not always confirmed; a researcher should be prepared to accept or reject the hypothesis based on the study findings.  

Research hypothesis checklist  

Following from above, here is a 10-point checklist for a good research hypothesis :  

• Testable: A research hypothesis should be able to be tested via experimentation or observation.  
• Specific: A research hypothesis should clearly state the relationship between the variables being studied.  
• Based on prior research: A research hypothesis should be based on existing knowledge and previous research in the field.  
• Falsifiable: A research hypothesis should be able to be disproven through testing.  
• Clear and concise: A research hypothesis should be stated in a clear and concise manner.  
• Logical: A research hypothesis should be logical and consistent with current understanding of the subject.  
• Relevant: A research hypothesis should be relevant to the research question and objectives.  
• Feasible: A research hypothesis should be feasible to test within the scope of the study.  
• Reflects the population: A research hypothesis should consider the population or sample being studied.  
• Uncomplicated: A good research hypothesis is written in a way that is easy for the target audience to understand.  

By following this research hypothesis checklist , you will be able to create a research hypothesis that is strong, well-constructed, and more likely to yield meaningful results.  

Types of research hypothesis  

Different types of research hypothesis are used in scientific research:  

1. Null hypothesis:

A null hypothesis states that there is no change in the dependent variable due to changes to the independent variable. This means that the results are due to chance and are not significant. A null hypothesis is denoted as H0 and is stated as the opposite of what the alternative hypothesis states.   

Example: “ The newly identified virus is not zoonotic .”  

2. Alternative hypothesis:

This states that there is a significant difference or relationship between the variables being studied. It is denoted as H1 or Ha and is usually accepted or rejected in favor of the null hypothesis.  

Example: “ The newly identified virus is zoonotic .”  

3. Directional hypothesis :

This specifies the direction of the relationship or difference between variables; therefore, it tends to use terms like increase, decrease, positive, negative, more, or less.   

Example: “ The inclusion of intervention X decreases infant mortality compared to the original treatment .”   

4. Non-directional hypothesis:

While it does not predict the exact direction or nature of the relationship between the two variables, a non-directional hypothesis states the existence of a relationship or difference between variables but not the direction, nature, or magnitude of the relationship. A non-directional hypothesis may be used when there is no underlying theory or when findings contradict previous research.  

Example, “ Cats and dogs differ in the amount of affection they express .”  

5. Simple hypothesis :

A simple hypothesis only predicts the relationship between one independent and another independent variable.  

Example: “ Applying sunscreen every day slows skin aging .”  

6 . Complex hypothesis :

A complex hypothesis states the relationship or difference between two or more independent and dependent variables.   

Example: “ Applying sunscreen every day slows skin aging, reduces sun burn, and reduces the chances of skin cancer .” (Here, the three dependent variables are slowing skin aging, reducing sun burn, and reducing the chances of skin cancer.)  

7. Associative hypothesis:  

An associative hypothesis states that a change in one variable results in the change of the other variable. The associative hypothesis defines interdependency between variables.  

Example: “ There is a positive association between physical activity levels and overall health .”  

8 . Causal hypothesis:

A causal hypothesis proposes a cause-and-effect interaction between variables.  

Example: “ Long-term alcohol use causes liver damage .”  

Note that some of the types of research hypothesis mentioned above might overlap. The types of hypothesis chosen will depend on the research question and the objective of the study.  

Research hypothesis examples  

Here are some good research hypothesis examples :  

“The use of a specific type of therapy will lead to a reduction in symptoms of depression in individuals with a history of major depressive disorder.”  

“Providing educational interventions on healthy eating habits will result in weight loss in overweight individuals.”  

“Plants that are exposed to certain types of music will grow taller than those that are not exposed to music.”  

“The use of the plant growth regulator X will lead to an increase in the number of flowers produced by plants.”  

Characteristics that make a research hypothesis weak are unclear variables, unoriginality, being too general or too vague, and being untestable. A weak hypothesis leads to weak research and improper methods.   

Some bad research hypothesis examples (and the reasons why they are “bad”) are as follows:  

“This study will show that treatment X is better than any other treatment . ” (This statement is not testable, too broad, and does not consider other treatments that may be effective.)  

“This study will prove that this type of therapy is effective for all mental disorders . ” (This statement is too broad and not testable as mental disorders are complex and different disorders may respond differently to different types of therapy.)  

“Plants can communicate with each other through telepathy . ” (This statement is not testable and lacks a scientific basis.)  

Importance of testable hypothesis  

If a research hypothesis is not testable, the results will not prove or disprove anything meaningful. The conclusions will be vague at best. A testable hypothesis helps a researcher focus on the study outcome and understand the implication of the question and the different variables involved. A testable hypothesis helps a researcher make precise predictions based on prior research.  

To be considered testable, there must be a way to prove that the hypothesis is true or false; further, the results of the hypothesis must be reproducible.  

Frequently Asked Questions (FAQs) on research hypothesis  

1. What is the difference between research question and research hypothesis ?  

A research question defines the problem and helps outline the study objective(s). It is an open-ended statement that is exploratory or probing in nature. Therefore, it does not make predictions or assumptions. It helps a researcher identify what information to collect. A research hypothesis , however, is a specific, testable prediction about the relationship between variables. Accordingly, it guides the study design and data analysis approach.

2. When to reject null hypothesis ?

A null hypothesis should be rejected when the evidence from a statistical test shows that it is unlikely to be true. This happens when the test statistic (e.g., p -value) is less than the defined significance level (e.g., 0.05). Rejecting the null hypothesis does not necessarily mean that the alternative hypothesis is true; it simply means that the evidence found is not compatible with the null hypothesis.  

3. How can I be sure my hypothesis is testable?  

A testable hypothesis should be specific and measurable, and it should state a clear relationship between variables that can be tested with data. To ensure that your hypothesis is testable, consider the following:  

• Clearly define the key variables in your hypothesis. You should be able to measure and manipulate these variables in a way that allows you to test the hypothesis.  
• The hypothesis should predict a specific outcome or relationship between variables that can be measured or quantified.   
• You should be able to collect the necessary data within the constraints of your study.  
• It should be possible for other researchers to replicate your study, using the same methods and variables.   
• Your hypothesis should be testable by using appropriate statistical analysis techniques, so you can draw conclusions, and make inferences about the population from the sample data.  
• The hypothesis should be able to be disproven or rejected through the collection of data.  

4. How do I revise my research hypothesis if my data does not support it?  

If your data does not support your research hypothesis , you will need to revise it or develop a new one. You should examine your data carefully and identify any patterns or anomalies, re-examine your research question, and/or revisit your theory to look for any alternative explanations for your results. Based on your review of the data, literature, and theories, modify your research hypothesis to better align it with the results you obtained. Use your revised hypothesis to guide your research design and data collection. It is important to remain objective throughout the process.  

5. I am performing exploratory research. Do I need to formulate a research hypothesis?  

As opposed to “confirmatory” research, where a researcher has some idea about the relationship between the variables under investigation, exploratory research (or hypothesis-generating research) looks into a completely new topic about which limited information is available. Therefore, the researcher will not have any prior hypotheses. In such cases, a researcher will need to develop a post-hoc hypothesis. A post-hoc research hypothesis is generated after these results are known.  

6. How is a research hypothesis different from a research question?

A research question is an inquiry about a specific topic or phenomenon, typically expressed as a question. It seeks to explore and understand a particular aspect of the research subject. In contrast, a research hypothesis is a specific statement or prediction that suggests an expected relationship between variables. It is formulated based on existing knowledge or theories and guides the research design and data analysis.

7. Can a research hypothesis change during the research process?

Yes, research hypotheses can change during the research process. As researchers collect and analyze data, new insights and information may emerge that require modification or refinement of the initial hypotheses. This can be due to unexpected findings, limitations in the original hypotheses, or the need to explore additional dimensions of the research topic. Flexibility is crucial in research, allowing for adaptation and adjustment of hypotheses to align with the evolving understanding of the subject matter.

8. How many hypotheses should be included in a research study?

The number of research hypotheses in a research study varies depending on the nature and scope of the research. It is not necessary to have multiple hypotheses in every study. Some studies may have only one primary hypothesis, while others may have several related hypotheses. The number of hypotheses should be determined based on the research objectives, research questions, and the complexity of the research topic. It is important to ensure that the hypotheses are focused, testable, and directly related to the research aims.

9. Can research hypotheses be used in qualitative research?

Yes, research hypotheses can be used in qualitative research, although they are more commonly associated with quantitative research. In qualitative research, hypotheses may be formulated as tentative or exploratory statements that guide the investigation. Instead of testing hypotheses through statistical analysis, qualitative researchers may use the hypotheses to guide data collection and analysis, seeking to uncover patterns, themes, or relationships within the qualitative data. The emphasis in qualitative research is often on generating insights and understanding rather than confirming or rejecting specific research hypotheses through statistical testing.

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Home » What is a Hypothesis – Types, Examples and Writing Guide

What is a Hypothesis – Types, Examples and Writing Guide

Table of Contents

Definition:

Hypothesis is an educated guess or proposed explanation for a phenomenon, based on some initial observations or data. It is a tentative statement that can be tested and potentially proven or disproven through further investigation and experimentation.

Hypothesis is often used in scientific research to guide the design of experiments and the collection and analysis of data. It is an essential element of the scientific method, as it allows researchers to make predictions about the outcome of their experiments and to test those predictions to determine their accuracy.

Types of Hypothesis

Types of Hypothesis are as follows:

Research Hypothesis

A research hypothesis is a statement that predicts a relationship between variables. It is usually formulated as a specific statement that can be tested through research, and it is often used in scientific research to guide the design of experiments.

Null Hypothesis

The null hypothesis is a statement that assumes there is no significant difference or relationship between variables. It is often used as a starting point for testing the research hypothesis, and if the results of the study reject the null hypothesis, it suggests that there is a significant difference or relationship between variables.

Alternative Hypothesis

An alternative hypothesis is a statement that assumes there is a significant difference or relationship between variables. It is often used as an alternative to the null hypothesis and is tested against the null hypothesis to determine which statement is more accurate.

Directional Hypothesis

A directional hypothesis is a statement that predicts the direction of the relationship between variables. For example, a researcher might predict that increasing the amount of exercise will result in a decrease in body weight.

Non-directional Hypothesis

A non-directional hypothesis is a statement that predicts the relationship between variables but does not specify the direction. For example, a researcher might predict that there is a relationship between the amount of exercise and body weight, but they do not specify whether increasing or decreasing exercise will affect body weight.

Statistical Hypothesis

A statistical hypothesis is a statement that assumes a particular statistical model or distribution for the data. It is often used in statistical analysis to test the significance of a particular result.

Composite Hypothesis

A composite hypothesis is a statement that assumes more than one condition or outcome. It can be divided into several sub-hypotheses, each of which represents a different possible outcome.

Empirical Hypothesis

An empirical hypothesis is a statement that is based on observed phenomena or data. It is often used in scientific research to develop theories or models that explain the observed phenomena.

Simple Hypothesis

A simple hypothesis is a statement that assumes only one outcome or condition. It is often used in scientific research to test a single variable or factor.

Complex Hypothesis

A complex hypothesis is a statement that assumes multiple outcomes or conditions. It is often used in scientific research to test the effects of multiple variables or factors on a particular outcome.

Applications of Hypothesis

Hypotheses are used in various fields to guide research and make predictions about the outcomes of experiments or observations. Here are some examples of how hypotheses are applied in different fields:

• Science : In scientific research, hypotheses are used to test the validity of theories and models that explain natural phenomena. For example, a hypothesis might be formulated to test the effects of a particular variable on a natural system, such as the effects of climate change on an ecosystem.
• Medicine : In medical research, hypotheses are used to test the effectiveness of treatments and therapies for specific conditions. For example, a hypothesis might be formulated to test the effects of a new drug on a particular disease.
• Psychology : In psychology, hypotheses are used to test theories and models of human behavior and cognition. For example, a hypothesis might be formulated to test the effects of a particular stimulus on the brain or behavior.
• Sociology : In sociology, hypotheses are used to test theories and models of social phenomena, such as the effects of social structures or institutions on human behavior. For example, a hypothesis might be formulated to test the effects of income inequality on crime rates.
• Business : In business research, hypotheses are used to test the validity of theories and models that explain business phenomena, such as consumer behavior or market trends. For example, a hypothesis might be formulated to test the effects of a new marketing campaign on consumer buying behavior.
• Engineering : In engineering, hypotheses are used to test the effectiveness of new technologies or designs. For example, a hypothesis might be formulated to test the efficiency of a new solar panel design.

How to write a Hypothesis

Here are the steps to follow when writing a hypothesis:

Identify the Research Question

The first step is to identify the research question that you want to answer through your study. This question should be clear, specific, and focused. It should be something that can be investigated empirically and that has some relevance or significance in the field.

Conduct a Literature Review

Before writing your hypothesis, it’s essential to conduct a thorough literature review to understand what is already known about the topic. This will help you to identify the research gap and formulate a hypothesis that builds on existing knowledge.

Determine the Variables

The next step is to identify the variables involved in the research question. A variable is any characteristic or factor that can vary or change. There are two types of variables: independent and dependent. The independent variable is the one that is manipulated or changed by the researcher, while the dependent variable is the one that is measured or observed as a result of the independent variable.

Formulate the Hypothesis

Based on the research question and the variables involved, you can now formulate your hypothesis. A hypothesis should be a clear and concise statement that predicts the relationship between the variables. It should be testable through empirical research and based on existing theory or evidence.

Write the Null Hypothesis

The null hypothesis is the opposite of the alternative hypothesis, which is the hypothesis that you are testing. The null hypothesis states that there is no significant difference or relationship between the variables. It is important to write the null hypothesis because it allows you to compare your results with what would be expected by chance.

Refine the Hypothesis

After formulating the hypothesis, it’s important to refine it and make it more precise. This may involve clarifying the variables, specifying the direction of the relationship, or making the hypothesis more testable.

Examples of Hypothesis

Here are a few examples of hypotheses in different fields:

• Psychology : “Increased exposure to violent video games leads to increased aggressive behavior in adolescents.”
• Biology : “Higher levels of carbon dioxide in the atmosphere will lead to increased plant growth.”
• Sociology : “Individuals who grow up in households with higher socioeconomic status will have higher levels of education and income as adults.”
• Education : “Implementing a new teaching method will result in higher student achievement scores.”
• Marketing : “Customers who receive a personalized email will be more likely to make a purchase than those who receive a generic email.”
• Physics : “An increase in temperature will cause an increase in the volume of a gas, assuming all other variables remain constant.”
• Medicine : “Consuming a diet high in saturated fats will increase the risk of developing heart disease.”

Purpose of Hypothesis

The purpose of a hypothesis is to provide a testable explanation for an observed phenomenon or a prediction of a future outcome based on existing knowledge or theories. A hypothesis is an essential part of the scientific method and helps to guide the research process by providing a clear focus for investigation. It enables scientists to design experiments or studies to gather evidence and data that can support or refute the proposed explanation or prediction.

The formulation of a hypothesis is based on existing knowledge, observations, and theories, and it should be specific, testable, and falsifiable. A specific hypothesis helps to define the research question, which is important in the research process as it guides the selection of an appropriate research design and methodology. Testability of the hypothesis means that it can be proven or disproven through empirical data collection and analysis. Falsifiability means that the hypothesis should be formulated in such a way that it can be proven wrong if it is incorrect.

In addition to guiding the research process, the testing of hypotheses can lead to new discoveries and advancements in scientific knowledge. When a hypothesis is supported by the data, it can be used to develop new theories or models to explain the observed phenomenon. When a hypothesis is not supported by the data, it can help to refine existing theories or prompt the development of new hypotheses to explain the phenomenon.

When to use Hypothesis

Here are some common situations in which hypotheses are used:

• In scientific research , hypotheses are used to guide the design of experiments and to help researchers make predictions about the outcomes of those experiments.
• In social science research , hypotheses are used to test theories about human behavior, social relationships, and other phenomena.
• I n business , hypotheses can be used to guide decisions about marketing, product development, and other areas. For example, a hypothesis might be that a new product will sell well in a particular market, and this hypothesis can be tested through market research.

Characteristics of Hypothesis

Here are some common characteristics of a hypothesis:

• Testable : A hypothesis must be able to be tested through observation or experimentation. This means that it must be possible to collect data that will either support or refute the hypothesis.
• Falsifiable : A hypothesis must be able to be proven false if it is not supported by the data. If a hypothesis cannot be falsified, then it is not a scientific hypothesis.
• Clear and concise : A hypothesis should be stated in a clear and concise manner so that it can be easily understood and tested.
• Based on existing knowledge : A hypothesis should be based on existing knowledge and research in the field. It should not be based on personal beliefs or opinions.
• Specific : A hypothesis should be specific in terms of the variables being tested and the predicted outcome. This will help to ensure that the research is focused and well-designed.
• Tentative: A hypothesis is a tentative statement or assumption that requires further testing and evidence to be confirmed or refuted. It is not a final conclusion or assertion.
• Relevant : A hypothesis should be relevant to the research question or problem being studied. It should address a gap in knowledge or provide a new perspective on the issue.

Advantages of Hypothesis

Hypotheses have several advantages in scientific research and experimentation:

• Guides research: A hypothesis provides a clear and specific direction for research. It helps to focus the research question, select appropriate methods and variables, and interpret the results.
• Predictive powe r: A hypothesis makes predictions about the outcome of research, which can be tested through experimentation. This allows researchers to evaluate the validity of the hypothesis and make new discoveries.
• Facilitates communication: A hypothesis provides a common language and framework for scientists to communicate with one another about their research. This helps to facilitate the exchange of ideas and promotes collaboration.
• Efficient use of resources: A hypothesis helps researchers to use their time, resources, and funding efficiently by directing them towards specific research questions and methods that are most likely to yield results.
• Provides a basis for further research: A hypothesis that is supported by data provides a basis for further research and exploration. It can lead to new hypotheses, theories, and discoveries.
• Increases objectivity: A hypothesis can help to increase objectivity in research by providing a clear and specific framework for testing and interpreting results. This can reduce bias and increase the reliability of research findings.

Limitations of Hypothesis

Some Limitations of the Hypothesis are as follows:

• Limited to observable phenomena: Hypotheses are limited to observable phenomena and cannot account for unobservable or intangible factors. This means that some research questions may not be amenable to hypothesis testing.
• May be inaccurate or incomplete: Hypotheses are based on existing knowledge and research, which may be incomplete or inaccurate. This can lead to flawed hypotheses and erroneous conclusions.
• May be biased: Hypotheses may be biased by the researcher’s own beliefs, values, or assumptions. This can lead to selective interpretation of data and a lack of objectivity in research.
• Cannot prove causation: A hypothesis can only show a correlation between variables, but it cannot prove causation. This requires further experimentation and analysis.
• Limited to specific contexts: Hypotheses are limited to specific contexts and may not be generalizable to other situations or populations. This means that results may not be applicable in other contexts or may require further testing.
• May be affected by chance : Hypotheses may be affected by chance or random variation, which can obscure or distort the true relationship between variables.

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Researcher, Academic Writer, Web developer

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How to Write a Research Hypothesis: Good & Bad Examples

What is a research hypothesis?

A research hypothesis is an attempt at explaining a phenomenon or the relationships between phenomena/variables in the real world. Hypotheses are sometimes called “educated guesses”, but they are in fact (or let’s say they should be) based on previous observations, existing theories, scientific evidence, and logic. A research hypothesis is also not a prediction—rather, predictions are ( should be) based on clearly formulated hypotheses. For example, “We tested the hypothesis that KLF2 knockout mice would show deficiencies in heart development” is an assumption or prediction, not a hypothesis. 

The research hypothesis at the basis of this prediction is “the product of the KLF2 gene is involved in the development of the cardiovascular system in mice”—and this hypothesis is probably (hopefully) based on a clear observation, such as that mice with low levels of Kruppel-like factor 2 (which KLF2 codes for) seem to have heart problems. From this hypothesis, you can derive the idea that a mouse in which this particular gene does not function cannot develop a normal cardiovascular system, and then make the prediction that we started with. 

What is the difference between a hypothesis and a prediction?

You might think that these are very subtle differences, and you will certainly come across many publications that do not contain an actual hypothesis or do not make these distinctions correctly. But considering that the formulation and testing of hypotheses is an integral part of the scientific method, it is good to be aware of the concepts underlying this approach. The two hallmarks of a scientific hypothesis are falsifiability (an evaluation standard that was introduced by the philosopher of science Karl Popper in 1934) and testability —if you cannot use experiments or data to decide whether an idea is true or false, then it is not a hypothesis (or at least a very bad one).

So, in a nutshell, you (1) look at existing evidence/theories, (2) come up with a hypothesis, (3) make a prediction that allows you to (4) design an experiment or data analysis to test it, and (5) come to a conclusion. Of course, not all studies have hypotheses (there is also exploratory or hypothesis-generating research), and you do not necessarily have to state your hypothesis as such in your paper. 

But for the sake of understanding the principles of the scientific method, let’s first take a closer look at the different types of hypotheses that research articles refer to and then give you a step-by-step guide for how to formulate a strong hypothesis for your own paper.

Types of Research Hypotheses

Hypotheses can be simple , which means they describe the relationship between one single independent variable (the one you observe variations in or plan to manipulate) and one single dependent variable (the one you expect to be affected by the variations/manipulation). If there are more variables on either side, you are dealing with a complex hypothesis. You can also distinguish hypotheses according to the kind of relationship between the variables you are interested in (e.g., causal or associative ). But apart from these variations, we are usually interested in what is called the “alternative hypothesis” and, in contrast to that, the “null hypothesis”. If you think these two should be listed the other way round, then you are right, logically speaking—the alternative should surely come second. However, since this is the hypothesis we (as researchers) are usually interested in, let’s start from there.

Alternative Hypothesis

If you predict a relationship between two variables in your study, then the research hypothesis that you formulate to describe that relationship is your alternative hypothesis (usually H1 in statistical terms). The goal of your hypothesis testing is thus to demonstrate that there is sufficient evidence that supports the alternative hypothesis, rather than evidence for the possibility that there is no such relationship. The alternative hypothesis is usually the research hypothesis of a study and is based on the literature, previous observations, and widely known theories. 

Null Hypothesis

The hypothesis that describes the other possible outcome, that is, that your variables are not related, is the null hypothesis ( H0 ). Based on your findings, you choose between the two hypotheses—usually that means that if your prediction was correct, you reject the null hypothesis and accept the alternative. Make sure, however, that you are not getting lost at this step of the thinking process: If your prediction is that there will be no difference or change, then you are trying to find support for the null hypothesis and reject H1. 

Directional Hypothesis

While the null hypothesis is obviously “static”, the alternative hypothesis can specify a direction for the observed relationship between variables—for example, that mice with higher expression levels of a certain protein are more active than those with lower levels. This is then called a one-tailed hypothesis. 

Another example for a directional one-tailed alternative hypothesis would be that 

H1: Attending private classes before important exams has a positive effect on performance. 

Your null hypothesis would then be that

H0: Attending private classes before important exams has no/a negative effect on performance.

Nondirectional Hypothesis

A nondirectional hypothesis does not specify the direction of the potentially observed effect, only that there is a relationship between the studied variables—this is called a two-tailed hypothesis. For instance, if you are studying a new drug that has shown some effects on pathways involved in a certain condition (e.g., anxiety) in vitro in the lab, but you can’t say for sure whether it will have the same effects in an animal model or maybe induce other/side effects that you can’t predict and potentially increase anxiety levels instead, you could state the two hypotheses like this:

H1: The only lab-tested drug (somehow) affects anxiety levels in an anxiety mouse model.

You then test this nondirectional alternative hypothesis against the null hypothesis:

H0: The only lab-tested drug has no effect on anxiety levels in an anxiety mouse model.

How to Write a Hypothesis for a Research Paper

Now that we understand the important distinctions between different kinds of research hypotheses, let’s look at a simple process of how to write a hypothesis.

Writing a Hypothesis Step:1

Ask a question, based on earlier research. Research always starts with a question, but one that takes into account what is already known about a topic or phenomenon. For example, if you are interested in whether people who have pets are happier than those who don’t, do a literature search and find out what has already been demonstrated. You will probably realize that yes, there is quite a bit of research that shows a relationship between happiness and owning a pet—and even studies that show that owning a dog is more beneficial than owning a cat ! Let’s say you are so intrigued by this finding that you wonder: 

What is it that makes dog owners even happier than cat owners? 

Let’s move on to Step 2 and find an answer to that question.

Writing a Hypothesis Step 2:

Formulate a strong hypothesis by answering your own question. Again, you don’t want to make things up, take unicorns into account, or repeat/ignore what has already been done. Looking at the dog-vs-cat papers your literature search returned, you see that most studies are based on self-report questionnaires on personality traits, mental health, and life satisfaction. What you don’t find is any data on actual (mental or physical) health measures, and no experiments. You therefore decide to make a bold claim come up with the carefully thought-through hypothesis that it’s maybe the lifestyle of the dog owners, which includes walking their dog several times per day, engaging in fun and healthy activities such as agility competitions, and taking them on trips, that gives them that extra boost in happiness. You could therefore answer your question in the following way:

Dog owners are happier than cat owners because of the dog-related activities they engage in.

Now you have to verify that your hypothesis fulfills the two requirements we introduced at the beginning of this resource article: falsifiability and testability . If it can’t be wrong and can’t be tested, it’s not a hypothesis. We are lucky, however, because yes, we can test whether owning a dog but not engaging in any of those activities leads to lower levels of happiness or well-being than owning a dog and playing and running around with them or taking them on trips.  

Writing a Hypothesis Step 3:

Make your predictions and define your variables. We have verified that we can test our hypothesis, but now we have to define all the relevant variables, design our experiment or data analysis, and make precise predictions. You could, for example, decide to study dog owners (not surprising at this point), let them fill in questionnaires about their lifestyle as well as their life satisfaction (as other studies did), and then compare two groups of active and inactive dog owners. Alternatively, if you want to go beyond the data that earlier studies produced and analyzed and directly manipulate the activity level of your dog owners to study the effect of that manipulation, you could invite them to your lab, select groups of participants with similar lifestyles, make them change their lifestyle (e.g., couch potato dog owners start agility classes, very active ones have to refrain from any fun activities for a certain period of time) and assess their happiness levels before and after the intervention. In both cases, your independent variable would be “ level of engagement in fun activities with dog” and your dependent variable would be happiness or well-being . 

Examples of a Good and Bad Hypothesis

Let’s look at a few examples of good and bad hypotheses to get you started.

Good Hypothesis Examples

Bad hypothesis examples, tips for writing a research hypothesis.

If you understood the distinction between a hypothesis and a prediction we made at the beginning of this article, then you will have no problem formulating your hypotheses and predictions correctly. To refresh your memory: We have to (1) look at existing evidence, (2) come up with a hypothesis, (3) make a prediction, and (4) design an experiment. For example, you could summarize your dog/happiness study like this:

(1) While research suggests that dog owners are happier than cat owners, there are no reports on what factors drive this difference. (2) We hypothesized that it is the fun activities that many dog owners (but very few cat owners) engage in with their pets that increases their happiness levels. (3) We thus predicted that preventing very active dog owners from engaging in such activities for some time and making very inactive dog owners take up such activities would lead to an increase and decrease in their overall self-ratings of happiness, respectively. (4) To test this, we invited dog owners into our lab, assessed their mental and emotional well-being through questionnaires, and then assigned them to an “active” and an “inactive” group, depending on… 

Note that you use “we hypothesize” only for your hypothesis, not for your experimental prediction, and “would” or “if – then” only for your prediction, not your hypothesis. A hypothesis that states that something “would” affect something else sounds as if you don’t have enough confidence to make a clear statement—in which case you can’t expect your readers to believe in your research either. Write in the present tense, don’t use modal verbs that express varying degrees of certainty (such as may, might, or could ), and remember that you are not drawing a conclusion while trying not to exaggerate but making a clear statement that you then, in a way, try to disprove . And if that happens, that is not something to fear but an important part of the scientific process.

Similarly, don’t use “we hypothesize” when you explain the implications of your research or make predictions in the conclusion section of your manuscript, since these are clearly not hypotheses in the true sense of the word. As we said earlier, you will find that many authors of academic articles do not seem to care too much about these rather subtle distinctions, but thinking very clearly about your own research will not only help you write better but also ensure that even that infamous Reviewer 2 will find fewer reasons to nitpick about your manuscript. 

Perfect Your Manuscript With Professional Editing

Now that you know how to write a strong research hypothesis for your research paper, you might be interested in our free AI Proofreader , Wordvice AI, which finds and fixes errors in grammar, punctuation, and word choice in academic texts. Or if you are interested in human proofreading , check out our English editing services , including research paper editing and manuscript editing .

On the Wordvice academic resources website , you can also find many more articles and other resources that can help you with writing the other parts of your research paper , with making a research paper outline before you put everything together, or with writing an effective cover letter once you are ready to submit.

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How to Write a Great Hypothesis

Hypothesis Definition, Format, Examples, and Tips

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Amy Morin, LCSW, is a psychotherapist and international bestselling author. Her books, including "13 Things Mentally Strong People Don't Do," have been translated into more than 40 languages. Her TEDx talk,  "The Secret of Becoming Mentally Strong," is one of the most viewed talks of all time.

Verywell / Alex Dos Diaz

• The Scientific Method

Hypothesis Format

Falsifiability of a hypothesis.

• Operationalization

Hypothesis Types

Hypotheses examples.

• Collecting Data

A hypothesis is a tentative statement about the relationship between two or more variables. It is a specific, testable prediction about what you expect to happen in a study. It is a preliminary answer to your question that helps guide the research process.

Consider a study designed to examine the relationship between sleep deprivation and test performance. The hypothesis might be: "This study is designed to assess the hypothesis that sleep-deprived people will perform worse on a test than individuals who are not sleep-deprived."

At a Glance

A hypothesis is crucial to scientific research because it offers a clear direction for what the researchers are looking to find. This allows them to design experiments to test their predictions and add to our scientific knowledge about the world. This article explores how a hypothesis is used in psychology research, how to write a good hypothesis, and the different types of hypotheses you might use.

The Hypothesis in the Scientific Method

In the scientific method , whether it involves research in psychology, biology, or some other area, a hypothesis represents what the researchers think will happen in an experiment. The scientific method involves the following steps:

• Forming a question
• Performing background research
• Creating a hypothesis
• Designing an experiment
• Collecting data
• Analyzing the results
• Drawing conclusions
• Communicating the results

The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. At this point, researchers then begin to develop a testable hypothesis.

Unless you are creating an exploratory study, your hypothesis should always explain what you  expect  to happen.

In a study exploring the effects of a particular drug, the hypothesis might be that researchers expect the drug to have some type of effect on the symptoms of a specific illness. In psychology, the hypothesis might focus on how a certain aspect of the environment might influence a particular behavior.

Remember, a hypothesis does not have to be correct. While the hypothesis predicts what the researchers expect to see, the goal of the research is to determine whether this guess is right or wrong. When conducting an experiment, researchers might explore numerous factors to determine which ones might contribute to the ultimate outcome.

In many cases, researchers may find that the results of an experiment  do not  support the original hypothesis. When writing up these results, the researchers might suggest other options that should be explored in future studies.

In many cases, researchers might draw a hypothesis from a specific theory or build on previous research. For example, prior research has shown that stress can impact the immune system. So a researcher might hypothesize: "People with high-stress levels will be more likely to contract a common cold after being exposed to the virus than people who have low-stress levels."

In other instances, researchers might look at commonly held beliefs or folk wisdom. "Birds of a feather flock together" is one example of folk adage that a psychologist might try to investigate. The researcher might pose a specific hypothesis that "People tend to select romantic partners who are similar to them in interests and educational level."

Elements of a Good Hypothesis

So how do you write a good hypothesis? When trying to come up with a hypothesis for your research or experiments, ask yourself the following questions:

• Is your hypothesis based on your research on a topic?
• Can your hypothesis be tested?
• Does your hypothesis include independent and dependent variables?

Before you come up with a specific hypothesis, spend some time doing background research. Once you have completed a literature review, start thinking about potential questions you still have. Pay attention to the discussion section in the  journal articles you read . Many authors will suggest questions that still need to be explored.

How to Formulate a Good Hypothesis

To form a hypothesis, you should take these steps:

• Collect as many observations about a topic or problem as you can.
• Evaluate these observations and look for possible causes of the problem.
• Create a list of possible explanations that you might want to explore.
• After you have developed some possible hypotheses, think of ways that you could confirm or disprove each hypothesis through experimentation. This is known as falsifiability.

In the scientific method ,  falsifiability is an important part of any valid hypothesis. In order to test a claim scientifically, it must be possible that the claim could be proven false.

Students sometimes confuse the idea of falsifiability with the idea that it means that something is false, which is not the case. What falsifiability means is that  if  something was false, then it is possible to demonstrate that it is false.

One of the hallmarks of pseudoscience is that it makes claims that cannot be refuted or proven false.

The Importance of Operational Definitions

A variable is a factor or element that can be changed and manipulated in ways that are observable and measurable. However, the researcher must also define how the variable will be manipulated and measured in the study.

Operational definitions are specific definitions for all relevant factors in a study. This process helps make vague or ambiguous concepts detailed and measurable.

For example, a researcher might operationally define the variable " test anxiety " as the results of a self-report measure of anxiety experienced during an exam. A "study habits" variable might be defined by the amount of studying that actually occurs as measured by time.

These precise descriptions are important because many things can be measured in various ways. Clearly defining these variables and how they are measured helps ensure that other researchers can replicate your results.

Replicability

One of the basic principles of any type of scientific research is that the results must be replicable.

Replication means repeating an experiment in the same way to produce the same results. By clearly detailing the specifics of how the variables were measured and manipulated, other researchers can better understand the results and repeat the study if needed.

Some variables are more difficult than others to define. For example, how would you operationally define a variable such as aggression ? For obvious ethical reasons, researchers cannot create a situation in which a person behaves aggressively toward others.

To measure this variable, the researcher must devise a measurement that assesses aggressive behavior without harming others. The researcher might utilize a simulated task to measure aggressiveness in this situation.

Hypothesis Checklist

• Does your hypothesis focus on something that you can actually test?
• Does your hypothesis include both an independent and dependent variable?
• Can you manipulate the variables?
• Can your hypothesis be tested without violating ethical standards?

The hypothesis you use will depend on what you are investigating and hoping to find. Some of the main types of hypotheses that you might use include:

• Simple hypothesis : This type of hypothesis suggests there is a relationship between one independent variable and one dependent variable.
• Complex hypothesis : This type suggests a relationship between three or more variables, such as two independent and dependent variables.
• Null hypothesis : This hypothesis suggests no relationship exists between two or more variables.
• Alternative hypothesis : This hypothesis states the opposite of the null hypothesis.
• Statistical hypothesis : This hypothesis uses statistical analysis to evaluate a representative population sample and then generalizes the findings to the larger group.
• Logical hypothesis : This hypothesis assumes a relationship between variables without collecting data or evidence.

A hypothesis often follows a basic format of "If {this happens} then {this will happen}." One way to structure your hypothesis is to describe what will happen to the  dependent variable  if you change the  independent variable .

The basic format might be: "If {these changes are made to a certain independent variable}, then we will observe {a change in a specific dependent variable}."

A few examples of simple hypotheses:

• "Students who eat breakfast will perform better on a math exam than students who do not eat breakfast."
• "Students who experience test anxiety before an English exam will get lower scores than students who do not experience test anxiety."​
• "Motorists who talk on the phone while driving will be more likely to make errors on a driving course than those who do not talk on the phone."
• "Children who receive a new reading intervention will have higher reading scores than students who do not receive the intervention."

Examples of a complex hypothesis include:

• "People with high-sugar diets and sedentary activity levels are more likely to develop depression."
• "Younger people who are regularly exposed to green, outdoor areas have better subjective well-being than older adults who have limited exposure to green spaces."

Examples of a null hypothesis include:

• "There is no difference in anxiety levels between people who take St. John's wort supplements and those who do not."
• "There is no difference in scores on a memory recall task between children and adults."
• "There is no difference in aggression levels between children who play first-person shooter games and those who do not."

Examples of an alternative hypothesis:

• "People who take St. John's wort supplements will have less anxiety than those who do not."
• "Adults will perform better on a memory task than children."
• "Children who play first-person shooter games will show higher levels of aggression than children who do not." 

Collecting Data on Your Hypothesis

Once a researcher has formed a testable hypothesis, the next step is to select a research design and start collecting data. The research method depends largely on exactly what they are studying. There are two basic types of research methods: descriptive research and experimental research.

Descriptive Research Methods

Descriptive research such as  case studies ,  naturalistic observations , and surveys are often used when  conducting an experiment is difficult or impossible. These methods are best used to describe different aspects of a behavior or psychological phenomenon.

Once a researcher has collected data using descriptive methods, a  correlational study  can examine how the variables are related. This research method might be used to investigate a hypothesis that is difficult to test experimentally.

Experimental Research Methods

Experimental methods  are used to demonstrate causal relationships between variables. In an experiment, the researcher systematically manipulates a variable of interest (known as the independent variable) and measures the effect on another variable (known as the dependent variable).

Unlike correlational studies, which can only be used to determine if there is a relationship between two variables, experimental methods can be used to determine the actual nature of the relationship—whether changes in one variable actually  cause  another to change.

The hypothesis is a critical part of any scientific exploration. It represents what researchers expect to find in a study or experiment. In situations where the hypothesis is unsupported by the research, the research still has value. Such research helps us better understand how different aspects of the natural world relate to one another. It also helps us develop new hypotheses that can then be tested in the future.

Thompson WH, Skau S. On the scope of scientific hypotheses .  R Soc Open Sci . 2023;10(8):230607. doi:10.1098/rsos.230607

Taran S, Adhikari NKJ, Fan E. Falsifiability in medicine: what clinicians can learn from Karl Popper [published correction appears in Intensive Care Med. 2021 Jun 17;:].  Intensive Care Med . 2021;47(9):1054-1056. doi:10.1007/s00134-021-06432-z

Eyler AA. Research Methods for Public Health . 1st ed. Springer Publishing Company; 2020. doi:10.1891/9780826182067.0004

Nosek BA, Errington TM. What is replication ?  PLoS Biol . 2020;18(3):e3000691. doi:10.1371/journal.pbio.3000691

Aggarwal R, Ranganathan P. Study designs: Part 2 - Descriptive studies .  Perspect Clin Res . 2019;10(1):34-36. doi:10.4103/picr.PICR_154_18

Nevid J. Psychology: Concepts and Applications. Wadworth, 2013.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

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• How to Write a Strong Hypothesis | Guide & Examples

How to Write a Strong Hypothesis | Guide & Examples

Published on 6 May 2022 by Shona McCombes .

A hypothesis is a statement that can be tested by scientific research. If you want to test a relationship between two or more variables, you need to write hypotheses before you start your experiment or data collection.

Table of contents

What is a hypothesis, developing a hypothesis (with example), hypothesis examples, frequently asked questions about writing hypotheses.

A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.

A hypothesis is not just a guess – it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations, and statistical analysis of data).

Variables in hypotheses

Hypotheses propose a relationship between two or more variables . An independent variable is something the researcher changes or controls. A dependent variable is something the researcher observes and measures.

In this example, the independent variable is exposure to the sun – the assumed cause . The dependent variable is the level of happiness – the assumed effect .

Prevent plagiarism, run a free check.

Step 1: ask a question.

Writing a hypothesis begins with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project.

Step 2: Do some preliminary research

Your initial answer to the question should be based on what is already known about the topic. Look for theories and previous studies to help you form educated assumptions about what your research will find.

At this stage, you might construct a conceptual framework to identify which variables you will study and what you think the relationships are between them. Sometimes, you’ll have to operationalise more complex constructs.

Step 3: Formulate your hypothesis

Now you should have some idea of what you expect to find. Write your initial answer to the question in a clear, concise sentence.

Step 4: Refine your hypothesis

You need to make sure your hypothesis is specific and testable. There are various ways of phrasing a hypothesis, but all the terms you use should have clear definitions, and the hypothesis should contain:

• The relevant variables
• The specific group being studied
• The predicted outcome of the experiment or analysis

Step 5: Phrase your hypothesis in three ways

To identify the variables, you can write a simple prediction in if … then form. The first part of the sentence states the independent variable and the second part states the dependent variable.

In academic research, hypotheses are more commonly phrased in terms of correlations or effects, where you directly state the predicted relationship between variables.

If you are comparing two groups, the hypothesis can state what difference you expect to find between them.

Step 6. Write a null hypothesis

If your research involves statistical hypothesis testing , you will also have to write a null hypothesis. The null hypothesis is the default position that there is no association between the variables. The null hypothesis is written as H 0 , while the alternative hypothesis is H 1 or H a .

Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses , by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.

A hypothesis is not just a guess. It should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations, and statistical analysis of data).

A research hypothesis is your proposed answer to your research question. The research hypothesis usually includes an explanation (‘ x affects y because …’).

A statistical hypothesis, on the other hand, is a mathematical statement about a population parameter. Statistical hypotheses always come in pairs: the null and alternative hypotheses. In a well-designed study , the statistical hypotheses correspond logically to the research hypothesis.

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How Do You Write a Hypothesis for a Research Paper?

Writing a hypothesis for a research paper can seem challenging, but it's a crucial step in the research process. A well-crafted hypothesis provides a clear direction for your study and helps you focus on what you aim to prove or disprove. This guide will walk you through the different types of hypotheses, how to formulate them, and the characteristics of a strong hypothesis.

Key Takeaways

• A hypothesis is a testable statement that predicts an outcome based on certain variables.
• There are different types of hypotheses, including null, alternative, directional, and non-directional.
• A good hypothesis should be clear, precise, and relevant to the research question.
• Common mistakes when writing a hypothesis include using vague language and making it too complex.
• Testing and refining your hypothesis is essential to ensure it aligns with your research findings.

Understanding the Role of a Hypothesis in Research

A hypothesis is a testable prediction about an outcome between two or more variables. It functions as a navigational tool in the research process, directing what you aim to predict and how.

Defining a Hypothesis

A hypothesis is a tentative statement about the relationship between two or more variables . It is sometimes called an "educated guess," but it should be based on previous observations, existing theories, scientific evidence, and logic. For example, "We tested the hypothesis that KLF2 knockout mice..."

Importance in the Research Process

In research, a hypothesis serves as the cornerstone for your empirical study. It not only lays out what you aim to investigate but also provides a structured approach for your data collection and analysis. A good research hypothesis is essential to developing scientific theories.

Common Misconceptions

One common misconception is that a hypothesis is just a random guess. In reality, it is a well-informed assumption that provides a context for data analysis and interpretation. Another misconception is that a hypothesis is the same as a prediction. While related, predictions are based on clearly formulated hypotheses.

Types of Hypotheses in Research Papers

Understanding the types of hypotheses can greatly enhance how you construct and work with hypotheses . While all hypotheses serve the essential function of guiding your study, there are varying purposes among the types of hypotheses. In addition, all hypotheses stand in contrast to the null hypothesis, or the assumption that there is no significant relationship between the variables.

Steps to Formulate a Strong Hypothesis

Formulating a strong hypothesis is a crucial step in the research process. It sets the foundation for your study and guides your data collection and analysis. Here are the steps to help you craft a robust hypothesis:

Identifying Research Variables

Start by identifying the key variables in your study. These are the elements that you will measure or manipulate. Clearly defining your variables helps in demystifying research and understanding the difference between a problem and a hypothesis.

Conducting Preliminary Research

Before you write your hypothesis, conduct preliminary research to understand the existing literature on your topic. This step ensures that your hypothesis is grounded in existing knowledge and helps you avoid common pitfalls. It also highlights the importance of distinguishing between a problem and a hypothesis in conducting effective research.

Crafting the Hypothesis Statement

Once you have identified your variables and conducted preliminary research, it's time to craft your hypothesis statement. Make sure it is clear, testable, and specific. A well-crafted hypothesis enhances the credibility and reliability of your research. Remember, a strong hypothesis is not just a guess; it is a statement that can be tested and potentially falsified.

By following these steps, you can formulate a hypothesis that provides clear objectives and steps in the research process, ultimately leading to more effective and reliable results.

Characteristics of a Good Hypothesis

A good hypothesis is essential for any research paper. It sets the stage for your study and guides your investigation. Here are some key characteristics to consider:

Testability and Falsifiability

A hypothesis must be testable, meaning you can verify it through experiments or observations. It should also be falsifiable, allowing you to prove it wrong. This is crucial for demystifying the concept of a thesis statement .

Clarity and Precision

Your hypothesis should be clear and precise, leaving no room for ambiguity. This helps in understanding the expected relationship between variables. A well-defined hypothesis can clarify the type of property you are investigating, such as feelings, perceptions, or behaviors.

Relevance to Research Question

The hypothesis should be directly related to your research question. It should be grounded in existing research or theoretical frameworks, ensuring its relevance and applicability. This makes your hypothesis not just a guess but a well-informed statement based on preliminary research .

Common Pitfalls to Avoid When Writing a Hypothesis

When crafting a hypothesis for your research paper, it's crucial to steer clear of certain common pitfalls. These mistakes can undermine the clarity and effectiveness of your hypothesis, leading to confusion and unreliable results. Here are some key pitfalls to avoid:

Overly Complex Hypotheses

A hypothesis should be straightforward and easy to understand. Avoid making it too complicated, as this can lead to design flaws in your study. Keep it simple and focused on a single idea or relationship.

Vague Language

Using vague or ambiguous language can make your hypothesis difficult to test. Be specific about the variables and the expected relationship between them. This clarity will help in designing your experiments and analyzing the data.

Ignoring Existing Literature

Before formulating your hypothesis, it's essential to review existing research. Ignoring previous studies can result in a hypothesis that lacks credibility and relevance. Ground your hypothesis in established theories and findings to ensure it is well-supported.

By avoiding these common pitfalls, you can create a strong and effective hypothesis that will guide your research and contribute to the field. Remember, a well-crafted hypothesis is the foundation of a successful research paper.

Examples of Well-Written Hypotheses

Examples from various disciplines.

To understand how to write a strong hypothesis, let's look at some examples from different fields. For instance, in biology, a hypothesis might be: "If plants are given more sunlight, then they will grow taller." This is a clear and testable statement. In psychology, you might see: "If people get more sleep, then their memory will improve." These examples show how hypotheses are often written as if-then statements .

Analyzing the Strengths and Weaknesses

When evaluating hypotheses, it's important to consider their strengths and weaknesses. A good hypothesis should be specific and measurable. For example, "Daily exercise reduces stress levels" is a strong hypothesis because it is clear and can be tested. On the other hand, a vague hypothesis like "Exercise is good" lacks specificity and is hard to measure. A research hypothesis explains a phenomenon or the relationships between variables in the real world.

Practical Tips for Improvement

To improve your hypothesis-writing skills, follow these tips:

• Be specific: Clearly define the variables and the expected relationship between them.
• Make it testable: Ensure that your hypothesis can be supported or refuted through experimentation or observation.
• Keep it simple: Avoid overly complex hypotheses that are difficult to test.
• Review existing literature: This helps you avoid common pitfalls and build on previous research.

By following these guidelines, you can craft hypotheses that are both strong and effective for your research paper.

Testing and Refining Your Hypothesis

Designing experiments.

To test your hypothesis, you need to design an experiment that will provide clear and reliable results. Start by identifying your independent and dependent variables. Make sure your experiment is structured to control for other factors that might influence the outcome. A well-designed experiment is crucial for obtaining valid results.

Collecting and Analyzing Data

Once your experiment is set up, it's time to collect data. Be meticulous in recording your observations and measurements. After collecting the data, analyze it to see if it supports your hypothesis. Use statistical tools to interpret the results and determine the significance of your findings.

Revising the Hypothesis Based on Findings

After analyzing your data, you may find that your hypothesis needs to be revised. This is a normal part of the scientific process. If your data does not support your hypothesis, consider what changes could make it more accurate. Sometimes, this means going back to the drawing board and conducting more preliminary research. Remember, the goal is to create a strong A/B testing hypothesis that will increase your probability of achieving success through your test.

Testing and refining your hypothesis is a crucial step in your research journey. It's where you see if your ideas hold up under scrutiny. Don't worry if things don't go as planned; this is all part of the process. Want to learn more about how to perfect your thesis? Visit our website for detailed guides and resources that can help you every step of the way.

Crafting a hypothesis for a research paper is a fundamental step in the scientific method. It sets the stage for your study by providing a clear, testable statement that guides your research. By understanding the different types of hypotheses and following a structured approach, you can formulate a hypothesis that is both meaningful and manageable. Remember, a well-written hypothesis not only clarifies your research focus but also helps in organizing your study effectively. As you embark on your research journey, keep refining your hypothesis to ensure it aligns with your findings and contributes to the broader field of knowledge.

Frequently Asked Questions

What is a hypothesis in a research paper.

A hypothesis is a statement that predicts the outcome of your research. It proposes a relationship between two variables and can be tested through experiments or observations.

Why is a hypothesis important in research?

A hypothesis guides your research by providing a clear focus. It helps you determine what you are trying to prove or disprove, making your study more structured and directed.

What are the different types of hypotheses?

There are several types of hypotheses, including the null hypothesis, alternative hypothesis, and directional vs. non-directional hypotheses. Each serves a different purpose in research.

How do I write a good hypothesis?

To write a good hypothesis, make sure it is clear, testable, and relevant to your research question. It should also be specific and concise, providing a clear direction for your study.

What are common mistakes to avoid when writing a hypothesis?

Common mistakes include making the hypothesis too complex, using vague language, and ignoring existing literature. It's important to keep it simple, clear, and based on prior research.

Can a hypothesis be changed during the research?

Yes, a hypothesis can be revised based on new findings or insights gained during the research process. It's important to remain flexible and open to adjustments as needed.

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Writing Guides  /  How to Write a Hypothesis w/ Strong Examples

How to Write a Hypothesis w/ Strong Examples

A hypothesis is a guess about what’s going to happen.  In research, the hypothesis is what you the researcher expects the outcome of an experiment, a study, a test, or a program to be.  It is a belief based on the evidence you have before you, the reasoning of your mind, and what prior experience tells you.  The hypothesis is not 100% guaranteed—that’s why there are different kinds of hypotheses.  In this article, we’ll explain what those are when they should be used.  So let’s dive in!

What is a Hypothesis / Definition

A hypothesis is like a bet:  you size things up and tell your mates exactly what you think is going to happen with respect to X, Y, Z.  It can also be like an explanation for a phenomenon, or a logical prediction of a possible causal correlation among multiple factors. In science—or, really, in any field, a hypothesis is used as a basis for further investigation.  For example, many qualitative or exploratory studies are conducted just so that the researcher in the end can formulate a hypothesis after all the data is collected an analyzed.

In short, it is an educated guess, based on existing knowledge or observation.  It is a way of proposing a possible explanation for a relationship between variables.

One thing to remember is this:  the key characteristic of a hypothesis is that it must be testable and potentially falsifiable. This means that it should be possible to design an experiment or observation that could potentially prove the hypothesis wrong.  That is a very important point to keep in mind.

For that reason, hypotheses are usually only formulated after conducting a preliminary review of existing literature, observations, or after obtaining a general understanding of the subject area. They are not random guesses.  They are grounded in some form of evidence or understanding of the phenomena being studied. The formulation of a hypothesis is a big step in the scientific method, as it defines the focus and direction of the research.  A lot of time is often spent simply on developing a good hypothesis.

Why?  A well-constructed hypothesis not only proposes an explanation for an observation but also often predicts measurable and testable outcomes. It is not merely a question, but rather a statement that includes a clear explanation or prediction. For example, rather than asking “Does temperature affect the growth of bacteria?”, a hypothesis would be something like this:  “If the temperature increases, then the growth rate of bacteria will increase.”  It is clear, measurable, testable, and potentially falsifiable.

In the scientific community, a hypothesis is respected when it has the potential to advance knowledge, regardless of whether testing proves it to be true or false. The process of testing, refining, or nullifying hypotheses through experimentation and observation is part of what research is all about.

 Different types of Hypotheses

Hypotheses can be categorized into several types.  Each type has a unique purpose in scientific research.  Understanding these types is helpful for formulating a hypothesis that is appropriate to your specific research question. The main types of hypotheses include the following:

• Simple Hypothesis : This formulates a relationship between two variables, one independent and one dependent. It is straightforward and concise, making it easy to test.  It is most often used in basic scientific experiments where the aim is to investigate the relationship between two variables, such as in laboratory experiments or controlled field studies.
• Complex Hypothesis : Unlike the simple hypothesis, a complex hypothesis involves multiple independent and dependent variables. It is used in studies that are looking at several factors simultaneously, where there is an interplay of multiple variables. These are common in fields like social sciences, behavioral studies, and large-scale environmental research.
• Directional Hypothesis : This type predicts the nature of the effect of the independent variable on the dependent variable. It specifies the direction of the expected relationship.  It tends to be used studies where prior research or theory has already suggested a specific direction of influence or effect, such as in clinical trials or in studies testing theoretical models.
• Non-directional Hypothesis : In contrast to the directional hypothesis, a non-directional hypothesis does not specify the direction of the relationship. It simply suggests that there is a relationship between variables without stating whether it is positive or negative.  It is often used in exploratory research where the direction of the relationship is not known, such as in early-stage psychological research or when studying new phenomena.
• Null Hypothesis : The null hypothesis states that there is no relationship between the variables being studied. It is a default position that assumes no effect until evidence suggests otherwise.  It is also a fundamental aspect of virtually all quantitative research, serving as the hypothesis that there is no effect or no difference, against which the alternative hypothesis is tested.
• Associative and Causal Hypotheses : Associative hypotheses propose a relationship between variables where changes in one variable correspond with changes in another.  They are common in observational studies, such as epidemiological research or surveys, where the goal is to identify correlations between variables.  Causal hypotheses go a step further by suggesting that one variable causes the change in the other.  They are used in experimental research designed to determine cause-and-effect relationships, such as randomized controlled trials in medical research or controlled experiments in psychology.

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How to Write a Good Hypothesis

Writing a good hypothesis is definitely a good skill to have in scientific research. But it is also one that you can definitely learn with some practice if you don’t already have it.  Just keep in mind that the hypothesis is what sets the stage for the entire investigation.  It guides the methods and analysis.  Everything you do in research stems from your research question and hypothesis.

Here are four essential steps to follow when crafting a hypothesis:

• Start with a Research Question

Every hypothesis begins with a clear, focused research question. This question should arise from a review of existing literature, some observations you have made in the field, or an information gap that is apparent in current knowledge. The question should be specific and researchable.  For example, instead of a broad question like “What affects plant growth?”, a more specific question would be “How does the amount of water affect the growth of sunflowers?”  This is a specific question, and sets up a stage for a perfect hypothesis.

How did you develop the question?  Easy.  You simply took a broad view first, and then began looking more closely.  You looked into the subject matter.  And, as with anything, the more you look into it, the more likely you are to have questions.  So, the most important step here is to get a sense of your subject.  The more you learn about it, the more likely you will be to have a good research question.  Ask yourself:  what about this subject would I like to know more about?  It helps if you have a genuine interest in the topic!  Say, for example, you want to know more about cryptocurrency security or scalability:  wouldn’t you start asking questions about how to achieve either?  And wouldn’t you need to know a bit about the topic before you can ask the right question?  Of course!  Apply that same logic to whatever subject you are researching and your research question will appear rather quickly.

• Do Preliminary Research

Before formulating your hypothesis, you of course should conduct preliminary research. This involves reviewing existing literature, understanding the current state of knowledge in the field, doing some critical thinking on the subject, and considering any existing theories and findings that might be relevant. This preliminary research helps in developing an educated guess.  If you do your background research well, your hypothesis will be grounded in existing knowledge.

This is basically the step that comes after you ask your research question but before you make a prediction about the subject matter.  Just like if you went to a racetrack and wanted to place a bet on a horse, you would research the horses, the owners, the teams, and make an educated guess about which one is most likely to win, doing preliminary research is the same:  you want to become very familiar with the topic—know it inside and out.  Then you will have everything you need to formulate your hypothesis.

• Formulate the Hypothesis

Based on your research question and preliminary research, now you can create your hypothesis. A good hypothesis should be clear, concise, and testable. It typically takes a statement form, predicting a potential outcome or relationship between variables. Make sure that your hypothesis is focused and answers your research question.  For example, a hypothesis for the research question stated above might be:   “If sunflower plants are watered with varying amounts of water, then those watered more frequently will grow taller due to better hydration.”

Keep in mind that when you reach the stage of formulating your hypothesis, you are essentially ready to make a statement that can be tested through research or experimentation. Your hypothesis should be as precise as possible. Don’t ever use ambiguous language in your hypothesis.  Also, you should be very specific about the variables involved and the expected relationship between them (if applicable).  For example, let’s look at the hypothesis we generated above:  “If sunflower plants are watered with varying amounts of water, then those watered more frequently will grow taller due to better hydration.”  We have clearly identified the variables (frequency of watering and plant growth height) and the expected outcome.

But what else should your hypothesis do?  Well, when we say it should address your research question, we mean it should be a logical extension of the question and your preliminary research.  If your research question is about the effect of watering frequency on sunflower growth, your hypothesis should specifically predict how these two variables are related.  It should not get into the types of soil, sunshine, temperature, or other variables unless these were brought up specifically in your research question.

Above all, you want your hypothesis to make a prediction. This means stating an expected outcome based on your understanding of the subject. The prediction is what will be tested through experiments or observations.

• Ensure Testability and Falsifiability

An important aspect of a good hypothesis is that it must be testable and potentially falsifiable. This means you should be able to conduct experiments or make observations that can support or refute the hypothesis. Avoid vague or broad statements that cannot be empirically tested.  Also, make sure that your hypothesis is potentially falsifiable; i.e., there should exist the possibility that it can be proven wrong.  For example, a hypothesis like “Sunflower plants need water to grow” is not falsifiable, as it is already a well-established fact.  But a hypothesis regarding frequency or amount of watering does have the potential to be nullified.

Therefore, keep that in mind during this step:  for a hypothesis to be testable, there must be a way to conduct an experiment or make observations that can confirm or disprove it. This means you should be able to measure or observe the variables involved. In the sunflower example, you can measure plant growth and control the frequency of watering very easily.  This is precisely what makes the hypothesis testable.

Another important point is falsifiability, as this is what separates scientific hypotheses from non-scientific ones.  If it doesn’t have the potential to be proven wrong, it’s not a hypothesis.  Being falsifiable doesn’t mean a hypothesis is false. It means that if the hypothesis is false, there is a way to demonstrate this. The potential for falsification is what allows researchers to make scientific progress no matter the problem or field.

Also, don’t be vague.  Your hypothesis needs to be specific: hypotheses that are too vague or broad are not useful in research, as there is no way to test them.  For example, saying “Water affects plant growth” is too vague.  How does water affect growth?  Is it the amount, frequency, or type of water?  Such a hypothesis needs to be more specific to be testable.  See what we mean?

Remember:   A hypothesis does not need to be correct.  It just needs to be testable.  It is a starting point for investigation. The value of a hypothesis lies in its ability to be tested.  The results of that test are what can potentially contribute to the existing body of scientific knowledge, regardless of whether the hypothesis is supported or refuted by the resulting data.

Hypothesis Examples

Simple hypothesis examples.

• Increasing the amount of natural light in a classroom will improve students’ test scores.
• Drinking at least eight glasses of water a day reduces the frequency of headaches in adults.
• Plant growth is faster when the plant is exposed to music for at least one hour per day.

Complex Hypothesis Examples

• Students’ academic performance is influenced by their study habits, family income, and the educational level of their parents.
• Employee productivity is affected by workplace environment, job satisfaction, and the level of personal stress the worker encounters both on the job and at home.
• The effectiveness of a weight loss program is dependent on the participant’s age, gender, and adherence to an appropriate diet plan.

Directional Hypothesis Examples

• Exposure to high levels of air pollution during pregnancy will increase the risk of asthma in children.
• A diet high in antioxidants will decrease the risk of heart disease in middle-aged adults.
• Regular physical exercise leads to a significant decrease in the symptoms of depression in adults.

Non-directional Hypothesis Examples

• There is a relationship between the amount of sleep a person gets and their level of stress.
• A change in classroom environment has an effect on student concentration.
• The introduction of ergonomics in the workplace environment impacts employee productivity.

Null Hypothesis Examples

• There is no significant difference in test scores between students who study in groups and those who study alone.
• Dietary changes have no effect on the improvement of symptoms in patients with type 2 diabetes.
• The new marketing strategy does not affect the sales numbers of the product.

Associative Hypothesis Examples

• There is an association between the number of hours spent on social media and the level of anxiety in teenagers.
• Daily consumption of green tea is associated with weight loss in adults.
• The frequency of public transport use correlates with the level of urban air pollution.

Causal Hypotheses Examples

• Implementing a school-based exercise program causes a reduction in obesity rates among children.
• High levels of job stress cause an increase in blood pressure.
• Smoking causes an increase in the risk of developing lung cancer.

In conclusion, understanding and effectively formulating a solid hypothesis is what scientific research and inquiry is all about—regardless of the type of work you’re doing.  It may be a simple, complex, directional, non-directional, null, associative, or causal hypothesis—no matter:  each type has its own specific purpose and guides the direction of a study in a different way. A simple hypothesis explores the relationship between two variables, while a complex hypothesis involves multiple variables. Directional hypotheses specify the expected direction of a relationship, whereas non-directional hypotheses do not. The null hypothesis, a fundamental aspect of statistical testing, posits no effect or relationship, serving as a baseline for analysis. Associative hypotheses explore correlations between variables, and causal hypotheses aim to establish cause-and-effect relationships.

The ability to craft a clear, concise, and testable hypothesis is important for any researcher. It is what shapes the course of the investigation.  It is also the backbone of the scientific method itself. A well-formulated hypothesis can lead to groundbreaking research or make significant contributions to knowledge in different fields.

As we have shown you with our examples, the hypothesis is more than a mere guess; it is an educated, testable prediction that guides you through the process of scientific discovery. When you master the art of hypothesis formulation, you can set off on your investigation with a clear roadmap and a clear sense of purpose.

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How to Write a Hypothesis – Steps & Tips

Published by Alaxendra Bets at August 14th, 2021 , Revised On October 26, 2023

What is a Research Hypothesis?

You can test a research statement with the help of experimental or theoretical research, known as a hypothesis.

If you want to find out the similarities, differences, and relationships between variables, you must write a testable hypothesis before compiling the data, performing analysis, and generating results to complete.

The data analysis and findings will help you test the hypothesis and see whether it is true or false. Here is all you need to know about how to write a hypothesis for a  dissertation .

Research Hypothesis Definition

Not sure what the meaning of the research hypothesis is?

A research hypothesis predicts an answer to the research question  based on existing theoretical knowledge or experimental data.

Some studies may have multiple hypothesis statements depending on the research question(s).  A research hypothesis must be based on formulas, facts, and theories. It should be testable by data analysis, observations, experiments, or other scientific methodologies that can refute or support the statement.

Variables in Hypothesis

Developing a hypothesis is easy. Most research studies have two or more variables in the hypothesis, particularly studies involving correlational and experimental research. The researcher can control or change the independent variable(s) while measuring and observing the independent variable(s).

“How long a student sleeps affects test scores.”

In the above statement, the dependent variable is the test score, while the independent variable is the length of time spent in sleep. Developing a hypothesis will be easy if you know your research’s dependent and independent variables.

Once you have developed a thesis statement, questions such as how to write a hypothesis for the dissertation and how to test a research hypothesis become pretty straightforward.

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Step-by-Step Guide on How to Write a Hypothesis

Here are the steps involved in how to write a hypothesis for a dissertation.

Step 1: Start with a Research Question

• Begin by asking a specific question about a topic of interest.
• This question should be clear, concise, and researchable.

Example: Does exposure to sunlight affect plant growth?

Step 2: Do Preliminary Research

• Before formulating a hypothesis, conduct background research to understand existing knowledge on the topic.
• Familiarise yourself with prior studies, theories, or observations related to the research question.

Step 3: Define Variables

• Independent Variable (IV): The factor that you change or manipulate in an experiment.
• Dependent Variable (DV): The factor that you measure.

Example: IV: Amount of sunlight exposure (e.g., 2 hours/day, 4 hours/day, 8 hours/day) DV: Plant growth (e.g., height in centimetres)

Step 4: Formulate the Hypothesis

• A hypothesis is a statement that predicts the relationship between variables.
• It is often written as an “if-then” statement.

Example: If plants receive more sunlight, then they will grow taller.

Step 5: Ensure it is Testable

A good hypothesis is empirically testable. This means you should be able to design an experiment or observation to test its validity.

Example: You can set up an experiment where plants are exposed to varying amounts of sunlight and then measure their growth over a period of time.

Step 6: Consider Potential Confounding Variables

• Confounding variables are factors other than the independent variable that might affect the outcome.
• It is important to identify these to ensure that they do not skew your results.

Example: Soil quality, water frequency, or type of plant can all affect growth. Consider keeping these constant in your experiment.

Step 7: Write the Null Hypothesis

• The null hypothesis is a statement that there is no effect or no relationship between the variables.
• It is what you aim to disprove or reject through your research.

Example: There is no difference in plant growth regardless of the amount of sunlight exposure.

Step 8: Test your Hypothesis

Design an experiment or conduct observations to test your hypothesis.

Example: Grow three sets of plants: one set exposed to 2 hours of sunlight daily, another exposed to 4 hours, and a third exposed to 8 hours. Measure and compare their growth after a set period.

Step 9: Analyse the Results

After testing, review your data to determine if it supports your hypothesis.

Step 10: Draw Conclusions

• Based on your findings, determine whether you can accept or reject the hypothesis.
• Remember, even if you reject your hypothesis, it’s a valuable result. It can guide future research and refine questions.

Three Ways to Phrase a Hypothesis

Try to use “if”… and “then”… to identify the variables. The independent variable should be present in the first part of the hypothesis, while the dependent variable will form the second part of the statement. Consider understanding the below research hypothesis example to create a specific, clear, and concise research hypothesis;

If an obese lady starts attending Zomba fitness classes, her health will improve.

In academic research, you can write the predicted variable relationship directly because most research studies correlate terms.

The number of Zomba fitness classes attended by the obese lady has a positive effect on health.

If your research compares two groups, then you can develop a hypothesis statement on their differences.

An obese lady who attended most Zumba fitness classes will have better health than those who attended a few.

How to Write a Null Hypothesis

If a statistical analysis is involved in your research, then you must create a null hypothesis. If you find any relationship between the variables, then the null hypothesis will be the default position that there is no relationship between them. H0 is the symbol for the null hypothesis, while the hypothesis is represented as H1. The null hypothesis will also answer your question, “How to test the research hypothesis in the dissertation.”

H0: The number of Zumba fitness classes attended by the obese lady does not affect her health.

H1: The number of Zumba fitness classes attended by obese lady positively affects health.

Also see:  Your Dissertation in Education

Hypothesis Examples

Research Question: Does the amount of sunlight a plant receives affect its growth? Hypothesis: Plants that receive more sunlight will grow taller than plants that receive less sunlight.

Research Question: Do students who eat breakfast perform better in school exams than those who don’t? Hypothesis: Students who eat a morning breakfast will score higher on school exams compared to students who skip breakfast.

Research Question: Does listening to music while studying impact a student’s ability to retain information? Hypothesis 1 (Directional): Students who listen to music while studying will retain less information than those who study in silence. Hypothesis 2 (Non-directional): There will be a difference in information retention between students who listen to music while studying and those who study in silence.

How can ResearchProspect Help?

If you are unsure about how to rest a research hypothesis in a dissertation or simply unsure about how to develop a hypothesis for your research, then you can take advantage of our dissertation services which cover every tiny aspect of a dissertation project you might need help with including but not limited to setting up a hypothesis and research questions,  help with individual chapters ,  full dissertation writing ,  statistical analysis , and much more.

Frequently Asked Questions

What are the 5 rules for writing a good hypothesis.

• Clear Statement: State a clear relationship between variables.
• Testable: Ensure it can be investigated and measured.
• Specific: Avoid vague terms, be precise in predictions.
• Falsifiable: Design to allow potential disproof.
• Relevant: Address research question and align with existing knowledge.

What is a hypothesis in simple words?

A hypothesis is an educated guess or prediction about something that can be tested. It is a statement that suggests a possible explanation for an event or phenomenon based on prior knowledge or observation. Scientists use hypotheses as a starting point for experiments to discover if they are true or false.

What is the hypothesis and examples?

A hypothesis is a testable prediction or explanation for an observation or phenomenon. For example, if plants are given sunlight, then they will grow. In this case, the hypothesis suggests that sunlight has a positive effect on plant growth. It can be tested by experimenting with plants in varying light conditions.

What is the hypothesis in research definition?

A hypothesis in research is a clear, testable statement predicting the possible outcome of a study based on prior knowledge and observation. It serves as the foundation for conducting experiments or investigations. Researchers test the validity of the hypothesis to draw conclusions and advance knowledge in a particular field.

Why is it called a hypothesis?

The term “hypothesis” originates from the Greek word “hypothesis,” which means “base” or “foundation.” It’s used to describe a foundational statement or proposition that can be tested. In scientific contexts, it denotes a tentative explanation for a phenomenon, serving as a starting point for investigation or experimentation.

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• How It Works

What Is A Research Hypothesis?

A Plain-Language Explainer + Practical Examples

Research Hypothesis 101

• What is a hypothesis ?
• What is a research hypothesis (scientific hypothesis)?
• Requirements for a research hypothesis
• Definition of a research hypothesis
• The null hypothesis

What is a hypothesis?

Let’s start with the general definition of a hypothesis (not a research hypothesis or scientific hypothesis), according to the Cambridge Dictionary:

Hypothesis: an idea or explanation for something that is based on known facts but has not yet been proved.

In other words, it’s a statement that provides an explanation for why or how something works, based on facts (or some reasonable assumptions), but that has not yet been specifically tested . For example, a hypothesis might look something like this:

Hypothesis: sleep impacts academic performance.

This statement predicts that academic performance will be influenced by the amount and/or quality of sleep a student engages in – sounds reasonable, right? It’s based on reasonable assumptions , underpinned by what we currently know about sleep and health (from the existing literature). So, loosely speaking, we could call it a hypothesis, at least by the dictionary definition.

But that’s not good enough…

Unfortunately, that’s not quite sophisticated enough to describe a research hypothesis (also sometimes called a scientific hypothesis), and it wouldn’t be acceptable in a dissertation, thesis or research paper . In the world of academic research, a statement needs a few more criteria to constitute a true research hypothesis .

What is a research hypothesis?

A research hypothesis (also called a scientific hypothesis) is a statement about the expected outcome of a study (for example, a dissertation or thesis). To constitute a quality hypothesis, the statement needs to have three attributes – specificity , clarity and testability .

Let’s take a look at these more closely.

Need a helping hand?

Hypothesis Essential #1: Specificity & Clarity

A good research hypothesis needs to be extremely clear and articulate about both what’ s being assessed (who or what variables are involved ) and the expected outcome (for example, a difference between groups, a relationship between variables, etc.).

Let’s stick with our sleepy students example and look at how this statement could be more specific and clear.

Hypothesis: Students who sleep at least 8 hours per night will, on average, achieve higher grades in standardised tests than students who sleep less than 8 hours a night.

As you can see, the statement is very specific as it identifies the variables involved (sleep hours and test grades), the parties involved (two groups of students), as well as the predicted relationship type (a positive relationship). There’s no ambiguity or uncertainty about who or what is involved in the statement, and the expected outcome is clear.

Contrast that to the original hypothesis we looked at – “Sleep impacts academic performance” – and you can see the difference. “Sleep” and “academic performance” are both comparatively vague , and there’s no indication of what the expected relationship direction is (more sleep or less sleep). As you can see, specificity and clarity are key.

Hypothesis Essential #2: Testability (Provability)

A statement must be testable to qualify as a research hypothesis. In other words, there needs to be a way to prove (or disprove) the statement. If it’s not testable, it’s not a hypothesis – simple as that.

For example, consider the hypothesis we mentioned earlier:

We could test this statement by undertaking a quantitative study involving two groups of students, one that gets 8 or more hours of sleep per night for a fixed period, and one that gets less. We could then compare the standardised test results for both groups to see if there’s a statistically significant difference.

Again, if you compare this to the original hypothesis we looked at – “Sleep impacts academic performance” – you can see that it would be quite difficult to test that statement, primarily because it isn’t specific enough. How much sleep? By who? What type of academic performance?

So, remember the mantra – if you can’t test it, it’s not a hypothesis 🙂

Defining A Research Hypothesis

You’re still with us? Great! Let’s recap and pin down a clear definition of a hypothesis.

A research hypothesis (or scientific hypothesis) is a statement about an expected relationship between variables, or explanation of an occurrence, that is clear, specific and testable.

So, when you write up hypotheses for your dissertation or thesis, make sure that they meet all these criteria. If you do, you’ll not only have rock-solid hypotheses but you’ll also ensure a clear focus for your entire research project.

What about the null hypothesis?

You may have also heard the terms null hypothesis , alternative hypothesis, or H-zero thrown around. At a simple level, the null hypothesis is the counter-proposal to the original hypothesis.

For example, if the hypothesis predicts that there is a relationship between two variables (for example, sleep and academic performance), the null hypothesis would predict that there is no relationship between those variables.

At a more technical level, the null hypothesis proposes that no statistical significance exists in a set of given observations and that any differences are due to chance alone.

And there you have it – hypotheses in a nutshell. 

If you have any questions, be sure to leave a comment below and we’ll do our best to help you. If you need hands-on help developing and testing your hypotheses, consider our private coaching service , where we hold your hand through the research journey.

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18 Comments

Very useful information. I benefit more from getting more information in this regard.

Very great insight,educative and informative. Please give meet deep critics on many research data of public international Law like human rights, environment, natural resources, law of the sea etc

In a book I read a distinction is made between null, research, and alternative hypothesis. As far as I understand, alternative and research hypotheses are the same. Can you please elaborate? Best Afshin

This is a self explanatory, easy going site. I will recommend this to my friends and colleagues.

Very good definition. How can I cite your definition in my thesis? Thank you. Is nul hypothesis compulsory in a research?

It’s a counter-proposal to be proven as a rejection

Please what is the difference between alternate hypothesis and research hypothesis?

It is a very good explanation. However, it limits hypotheses to statistically tasteable ideas. What about for qualitative researches or other researches that involve quantitative data that don’t need statistical tests?

In qualitative research, one typically uses propositions, not hypotheses.

could you please elaborate it more

I’ve benefited greatly from these notes, thank you.

This is very helpful

well articulated ideas are presented here, thank you for being reliable sources of information

Excellent. Thanks for being clear and sound about the research methodology and hypothesis (quantitative research)

I have only a simple question regarding the null hypothesis. – Is the null hypothesis (Ho) known as the reversible hypothesis of the alternative hypothesis (H1? – How to test it in academic research?

Angelo Loye Very fantastic information. From here I am going straightaway to present the research hypothesis One question, do we apply hypothesis in qualitative research? What nul hypothesi Otherwise I appreciate your research methodo

this is very important note help me much more

Hi” best wishes to you and your very nice blog” 

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Research Paper Guide

How To Write A Hypothesis

Last updated on: Feb 8, 2023

How to Write a Hypothesis - A Step-by-Step Guide

By: Nathan D.

Reviewed By: Rylee W.

Published on: Jul 16, 2019

A hypothesis is generally a statement that a researcher has to test through scientific methods subjectively. Unlike a thesis statement, a hypothesis does not require a researcher to prove it right in any circumstance.

It is a statement that is developed prior to research, experiment, or data collection. In simple words, it is a proposed explanation for any idea, study, or phenomenon.

For  research paper writing , thesis, case studies, or dissertation, you will have to write a hypothesis first. Continue reading the article to learn how to write a good hypothesis effectively.

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What is a Hypothesis?

A hypothesis is a proposed or supposition explanation that a researcher forms based on limited reference about a specific phenomenon. This statement is further investigated to analyze its validity and significance.

A hypothesis statement is an initial point from where an investigation begins. Moreover, it translates the major research question into a prediction.

In professional terms, a hypothesis is an idea whose merit requires evaluation and interpretation. For this purpose, the researcher needs to define the specifics of the hypothesis in operational terms.

It requires a researcher to study in detail whether to approve it or disapprove of it. In this process, the hypothesis either becomes a part of the theory, or a theory itself.

Functions of Hypothesis

Learning the correct writing procedure is not enough if you are not aware of the basic functions that your hypothesis performs. To make your hypothesis stand out, understand the below-given functions

• First and foremost, a hypothesis contributes to making your research, observation, and experiment possible
• This helps in starting the basic investigation about the subject
• It verifies the observation
• It provides the right direction to your inquiries

Components of a Hypothesis

Like other sentences and statements, a hypothesis has major components that play a significant role in making it impactful. It is essential to learn about these parts when you are researching academics.

The following are the different components of the hypothesis:

How to Write a Hypothesis?

Just like every other formal or academic task, writing a hypothesis includes a process. Although there are no set of rules to follow while developing a hypothesis.

However, it is recommended that you follow some steps to ensure a quality statement. These steps will make it easier for you to formulate a strong hypothesis to provide a great direction for your research.

Following is a step-by-step- procedure to write a hypothesis.

1. Develop a Question

When writing a hypothesis, the first thing is to develop a research question that you want to answer in your research. The question that you will formulate should be specific, focused, and researchable within the constraints of your assignment.

2. Conduct a Basic Research

The initial answer to your research question will be spontaneous and based on pre-existing knowledge about the subject. Search for theories and information to form a basic assumption that you will investigate further.

At this stage of creating a hypothesis, a researcher can develop a conceptual framework to identify the variables and their relationship.

3. Develop a Rough Hypothesis

Formulate a rough statement on the available knowledge to provide an idea about what to expect from your research. Brainstorm the answer for this raw question and present it into a clear and concise sentence.

4. Refine the Statement Made

Now that you have a rough statement in hand, it is time to refine and make it a testable hypothesis. There are several ways to shape your hypothesis, but you can arrange your statement keeping in view the parts.

Make sure that your refined statement must contain the following things:

• Relevant variables
• The group being studied
• The predicted result of the research or experiment

5. Phrasing the Hypothesis

The hypothesis can be phrased in three ways. Depending on the requirement of the research and the field type, select a phrasing pattern.

• To phrase the hypothesis, identify the variables, use a simple prediction pattern of “if...then” form. Present the independent variable first and then the dependent variable in your hypothesis statement.
• When developing a hypothesis for academic research, you can choose correlation and effect phrasing. In this way, you directly present the predicted relationship between the two variables.
• If the statement compares the two groups, the paraphrasing of the hypothesis can be done by stating the expected difference.

6. Write a Null Hypothesis

If your research is based on statistical testing of the hypothesis, you will have to present a null hypothesis. The null hypothesis states that there is no relationship or association between the two variables.

How to Write a Null Hypothesis?

There are two types of hypotheses, the null hypothesis, and the alternative hypothesis. A null hypothesis states that there is no difference between certain characteristics of a population while an alternative hypothesis states otherwise.

So, how does a null hypothesis work? Below is a four-step process to come up with a null hypothesis.

• The analyst will come up with two hypotheses and test them.
• Next, he formulates an analysis plan and decides the ways through which those hypotheses would be analyzed.
• The sample data and hypotheses are evaluated and analyzed.
• The final step is to analyze the acquired results and decide whether the null hypothesis is correct or not.

Other than null analysis, alternative hypotheses are also used. An alternative hypothesis is opposite to the null hypothesis and they are independent of each other.

What kind of Sources should I Add to my Hypothesis

It is important to look for credible and relevant sources of information while writing a hypothesis for your  research proposal . A researcher has to consult these sources to check the reliability and validity of your primary idea.

In case you are wondering what sources will work best for your hypothesis, check out the following:

• Find relevant phenomena that have some resemblance to yours
• Evaluate the studies and observations from the past
• Analyze what the current time has to say about the idea
• Search the competitor’s ideas and opinions
• Analyze scientific theories
• Dig deeper into the patterns that influence people and their thinking

Types of Hypothesis

Depending on the field and  research methods  to collect data, hypotheses can have different types. When writing a research paper, it is essential to know all the types well to form a strong and relevant hypothesis.

Following are the six main types of hypothesis:

• Simple Hypothesis  - A simple hypothesis is a statement that shows a relationship between two variables; an independent and dependent variable. For example, doing exercise can help you lose weight faster. Here doing exercise is an independent variable while losing weight is dependent.
• Complex Hypothesis  - A complex hypothesis presents a relationship between two or more dependent and independent variables. For example, exercising and eating lots of vegetables can reduce weight and other fatal diseases such as heart disease.
• Directional Hypothesis  - A directional hypothesis is a statement that presents the researcher’s commitment to a particular result. Moreover, the relationship between different variables also predicts its nature. For example, people who are sleep-deprived for 24 hours will have more cold symptoms than those who oversleep.
• Non-Directional Hypothesis  - A non-directional hypothesis is used when there is no theory involved. It shows an existing relationship between two variables without highlighting the exact relationship’s nature.
• Null Hypothesis  - A null hypothesis states that there is no relationship between the two variables. Similarly, it also contended that there is not enough information to state the scientific hypothesis. The ‘H0’ symbol denotes this hypothesis.
• Alternative Hypothesis  - It is a statement that the research forms when he disapproves the null hypothesis. As the name suggests, it is an alternative statement to your null hypothesis highlighting the relationship between the variables. It is denoted by ‘H1’.
• Associative and Causal Hypothesis  - In an associative hypothesis, a change in one variable results in a difference in the other variable. On the other hand, the causal hypothesis presents a cause and effect interaction between the two variables.

Characteristics of a Good Hypothesis

Professional writers believe that a hypothesis has certain features that help it become stronger and more effective. These characteristics include:

• To make the hypothesis credible, it should be clear and precise
• If you have chosen a hypothesis type that will state the relationship between the two variables, it should be obvious
• A strong hypothesis is specific and has clear scope for conducting more studies and tests
• The explanation of the hypothesis must be simple. Keep in mind that the simplicity of the hypothesis has nothing to do with its significance

Only a strong hypothesis will motivate the readers to read the entire paper. So make sure that you carefully develop a hypothesis for your research.

Hypothesis Examples

If you are writing a paper for the first time, it is suggested by professionals to go through a few examples. It will help you understand the pattern in which you should be working.

Below-given are examples of how hypotheses are developed for different research experiments.

HOW TO WRITE A HYPOTHESIS FOR RESEARCH PAPER

HOW TO WRITE A HYPOTHESIS FOR SCIENTIFIC RESEARCH

Going through these examples will help you understand better which course of action should be chosen for your research. If it is still difficult for you to look for sources and write a compelling hypothesis, get help from professionals.

5StarEssays.com is a professional ‘ write my essay for me? ’ service that provides different academic writing services. Whether you are looking for an expert to write a compelling essay or any form of paper, we have your back.

Our experts draft all your assignments carefully, ensuring that each part is well-written and structured. Get your assignment today by simply placing your order at the most affordable price.

Frequently Asked Questions

How do you turn a question into a hypothesis.

You can change and transform a question into a hypothesis by changing it into a statement.

Is a hypothesis a prediction?

No, a hypothesis is not a prediction but rather a possibility. The researcher ‘hopes’ to obtain a certain kind of result through the experimentation. This possibility or expected results are the hypothesis.

Can a hypothesis be a question?

No, a hypothesis is and should be a statement and not a question.

Do all research papers have a hypothesis?

No, some research papers are based on exploratory research, which is used to develop the hypothesis. So, such a research paper does not need a hypothesis.

Masters Essay, College Admission Essay

Nathan completed his Ph.D. in journalism and has been writing articles for well-respected publications for many years now. His work is carefully researched and insightful, showing a true passion for the written word. Nathan's clients appreciate his expertise, deep understanding of the process, and ability to communicate difficult concepts clearly.

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How to Write a Hypothesis? Types and Examples 

All research studies involve the use of the scientific method, which is a mathematical and experimental technique used to conduct experiments by developing and testing a hypothesis or a prediction about an outcome. Simply put, a hypothesis is a suggested solution to a problem. It includes elements that are expressed in terms of relationships with each other to explain a condition or an assumption that hasn’t been verified using facts. 1 The typical steps in a scientific method include developing such a hypothesis, testing it through various methods, and then modifying it based on the outcomes of the experiments.  

A research hypothesis can be defined as a specific, testable prediction about the anticipated results of a study. 2 Hypotheses help guide the research process and supplement the aim of the study. After several rounds of testing, hypotheses can help develop scientific theories. 3 Hypotheses are often written as if-then statements. 

Here are two hypothesis examples: 

Dandelions growing in nitrogen-rich soils for two weeks develop larger leaves than those in nitrogen-poor soils because nitrogen stimulates vegetative growth. 4  

If a company offers flexible work hours, then their employees will be happier at work. 5  

Table of Contents

• What is a hypothesis? 
• Types of hypotheses 
• Characteristics of a hypothesis 
• Functions of a hypothesis 
• How to write a hypothesis 
• Hypothesis examples 
• Frequently asked questions 

What is a hypothesis?

A hypothesis expresses an expected relationship between variables in a study and is developed before conducting any research. Hypotheses are not opinions but rather are expected relationships based on facts and observations. They help support scientific research and expand existing knowledge. An incorrectly formulated hypothesis can affect the entire experiment leading to errors in the results so it’s important to know how to formulate a hypothesis and develop it carefully.

A few sources of a hypothesis include observations from prior studies, current research and experiences, competitors, scientific theories, and general conditions that can influence people. Figure 1 depicts the different steps in a research design and shows where exactly in the process a hypothesis is developed. 4  

There are seven different types of hypotheses—simple, complex, directional, nondirectional, associative and causal, null, and alternative. 

Types of hypotheses

The seven types of hypotheses are listed below: 5 , 6,7  

• Simple : Predicts the relationship between a single dependent variable and a single independent variable. 

Example: Exercising in the morning every day will increase your productivity.  

• Complex : Predicts the relationship between two or more variables. 

Example: Spending three hours or more on social media daily will negatively affect children’s mental health and productivity, more than that of adults.  

• Directional : Specifies the expected direction to be followed and uses terms like increase, decrease, positive, negative, more, or less. 

Example: The inclusion of intervention X decreases infant mortality compared to the original treatment.  

• Non-directional : Does not predict the exact direction, nature, or magnitude of the relationship between two variables but rather states the existence of a relationship. This hypothesis may be used when there is no underlying theory or if findings contradict prior research. 

Example: Cats and dogs differ in the amount of affection they express.  

• Associative and causal : An associative hypothesis suggests an interdependency between variables, that is, how a change in one variable changes the other.  

Example: There is a positive association between physical activity levels and overall health.  

A causal hypothesis, on the other hand, expresses a cause-and-effect association between variables. 

Example: Long-term alcohol use causes liver damage.  

• Null : Claims that the original hypothesis is false by showing that there is no relationship between the variables. 

Example: Sleep duration does not have any effect on productivity.  

• Alternative : States the opposite of the null hypothesis, that is, a relationship exists between two variables. 

Example: Sleep duration affects productivity.  

Characteristics of a hypothesis

So, what makes a good hypothesis? Here are some important characteristics of a hypothesis. 8,9  

• Testable : You must be able to test the hypothesis using scientific methods to either accept or reject the prediction. 
• Falsifiable : It should be possible to collect data that reject rather than support the hypothesis. 
• Logical : Hypotheses shouldn’t be a random guess but rather should be based on previous theories, observations, prior research, and logical reasoning. 
• Positive : The hypothesis statement about the existence of an association should be positive, that is, it should not suggest that an association does not exist. Therefore, the language used and knowing how to phrase a hypothesis is very important. 
• Clear and accurate : The language used should be easily comprehensible and use correct terminology. 
• Relevant : The hypothesis should be relevant and specific to the research question. 
• Structure : Should include all the elements that make a good hypothesis: variables, relationship, and outcome. 

Functions of a hypothesis

The following list mentions some important functions of a hypothesis: 1  

• Maintains the direction and progress of the research. 
• Expresses the important assumptions underlying the proposition in a single statement. 
• Establishes a suitable context for researchers to begin their investigation and for readers who are referring to the final report. 
• Provides an explanation for the occurrence of a specific phenomenon. 
• Ensures selection of appropriate and accurate facts necessary and relevant to the research subject. 

To summarize, a hypothesis provides the conceptual elements that complete the known data, conceptual relationships that systematize unordered elements, and conceptual meanings and interpretations that explain the unknown phenomena. 1  

How to write a hypothesis

Listed below are the main steps explaining how to write a hypothesis. 2,4,5  

• Make an observation and identify variables : Observe the subject in question and try to recognize a pattern or a relationship between the variables involved. This step provides essential background information to begin your research.  

For example, if you notice that an office’s vending machine frequently runs out of a specific snack, you may predict that more people in the office choose that snack over another. 

• Identify the main research question : After identifying a subject and recognizing a pattern, the next step is to ask a question that your hypothesis will answer.  

For example, after observing employees’ break times at work, you could ask “why do more employees take breaks in the morning rather than in the afternoon?” 

• Conduct some preliminary research to ensure originality and novelty : Your initial answer, which is your hypothesis, to the question is based on some pre-existing information about the subject. However, to ensure that your hypothesis has not been asked before or that it has been asked but rejected by other researchers you would need to gather additional information.  

For example, based on your observations you might state a hypothesis that employees work more efficiently when the air conditioning in the office is set at a lower temperature. However, during your preliminary research you find that this hypothesis was proven incorrect by a prior study. 

• Develop a general statement : After your preliminary research has confirmed the originality of your proposed answer, draft a general statement that includes all variables, subjects, and predicted outcome. The statement could be if/then or declarative.  
• Finalize the hypothesis statement : Use the PICOT model, which clarifies how to word a hypothesis effectively, when finalizing the statement. This model lists the important components required to write a hypothesis. 

P opulation: The specific group or individual who is the main subject of the research 

I nterest: The main concern of the study/research question 

C omparison: The main alternative group 

O utcome: The expected results  

T ime: Duration of the experiment 

Once you’ve finalized your hypothesis statement you would need to conduct experiments to test whether the hypothesis is true or false. 

Hypothesis examples

The following table provides examples of different types of hypotheses. 10 ,11  

Key takeaways  

Here’s a summary of all the key points discussed in this article about how to write a hypothesis. 

• A hypothesis is an assumption about an association between variables made based on limited evidence, which should be tested. 
• A hypothesis has four parts—the research question, independent variable, dependent variable, and the proposed relationship between the variables.   
• The statement should be clear, concise, testable, logical, and falsifiable. 
• There are seven types of hypotheses—simple, complex, directional, non-directional, associative and causal, null, and alternative. 
• A hypothesis provides a focus and direction for the research to progress. 
• A hypothesis plays an important role in the scientific method by helping to create an appropriate experimental design. 

Frequently asked questions

Hypotheses and research questions have different objectives and structure. The following table lists some major differences between the two. 9  

Here are a few examples to differentiate between a research question and hypothesis. 

Yes, here’s a simple checklist to help you gauge the effectiveness of your hypothesis. 9   1. When writing a hypothesis statement, check if it:  2. Predicts the relationship between the stated variables and the expected outcome.  3. Uses simple and concise language and is not wordy.  4. Does not assume readers’ knowledge about the subject.  5. Has observable, falsifiable, and testable results. 

As mentioned earlier in this article, a hypothesis is an assumption or prediction about an association between variables based on observations and simple evidence. These statements are usually generic. Research objectives, on the other hand, are more specific and dictated by hypotheses. The same hypothesis can be tested using different methods and the research objectives could be different in each case.     For example, Louis Pasteur observed that food lasts longer at higher altitudes, reasoned that it could be because the air at higher altitudes is cleaner (with fewer or no germs), and tested the hypothesis by exposing food to air cleaned in the laboratory. 12 Thus, a hypothesis is predictive—if the reasoning is correct, X will lead to Y—and research objectives are developed to test these predictions. 

Null hypothesis testing is a method to decide between two assumptions or predictions between variables (null and alternative hypotheses) in a statistical relationship in a sample. The null hypothesis, denoted as H 0 , claims that no relationship exists between variables in a population and any relationship in the sample reflects a sampling error or occurrence by chance. The alternative hypothesis, denoted as H 1 , claims that there is a relationship in the population. In every study, researchers need to decide whether the relationship in a sample occurred by chance or reflects a relationship in the population. This is done by hypothesis testing using the following steps: 13   1. Assume that the null hypothesis is true.  2. Determine how likely the sample relationship would be if the null hypothesis were true. This probability is called the p value.  3. If the sample relationship would be extremely unlikely, reject the null hypothesis and accept the alternative hypothesis. If the relationship would not be unlikely, accept the null hypothesis. 

To summarize, researchers should know how to write a good hypothesis to ensure that their research progresses in the required direction. A hypothesis is a testable prediction about any behavior or relationship between variables, usually based on facts and observation, and states an expected outcome.  

We hope this article has provided you with essential insight into the different types of hypotheses and their functions so that you can use them appropriately in your next research project. 

References  

• Dalen, DVV. The function of hypotheses in research. Proquest website. Accessed April 8, 2024. https://www.proquest.com/docview/1437933010?pq-origsite=gscholar&fromopenview=true&sourcetype=Scholarly%20Journals&imgSeq=1  
• McLeod S. Research hypothesis in psychology: Types & examples. SimplyPsychology website. Updated December 13, 2023. Accessed April 9, 2024. https://www.simplypsychology.org/what-is-a-hypotheses.html  
• Scientific method. Britannica website. Updated March 14, 2024. Accessed April 9, 2024. https://www.britannica.com/science/scientific-method  
• The hypothesis in science writing. Accessed April 10, 2024. https://berks.psu.edu/sites/berks/files/campus/HypothesisHandout_Final.pdf  
• How to develop a hypothesis (with elements, types, and examples). Indeed.com website. Updated February 3, 2023. Accessed April 10, 2024. https://www.indeed.com/career-advice/career-development/how-to-write-a-hypothesis  
• Types of research hypotheses. Excelsior online writing lab. Accessed April 11, 2024. https://owl.excelsior.edu/research/research-hypotheses/types-of-research-hypotheses/  
• What is a research hypothesis: how to write it, types, and examples. Researcher.life website. Published February 8, 2023. Accessed April 11, 2024. https://researcher.life/blog/article/how-to-write-a-research-hypothesis-definition-types-examples/  
• Developing a hypothesis. Pressbooks website. Accessed April 12, 2024. https://opentext.wsu.edu/carriecuttler/chapter/developing-a-hypothesis/  
• What is and how to write a good hypothesis in research. Elsevier author services website. Accessed April 12, 2024. https://scientific-publishing.webshop.elsevier.com/manuscript-preparation/what-how-write-good-hypothesis-research/  
• How to write a great hypothesis. Verywellmind website. Updated March 12, 2023. Accessed April 13, 2024. https://www.verywellmind.com/what-is-a-hypothesis-2795239  
• 15 Hypothesis examples. Helpfulprofessor.com Published September 8, 2023. Accessed March 14, 2024. https://helpfulprofessor.com/hypothesis-examples/ 
• Editage insights. What is the interconnectivity between research objectives and hypothesis? Published February 24, 2021. Accessed April 13, 2024. https://www.editage.com/insights/what-is-the-interconnectivity-between-research-objectives-and-hypothesis  
• Understanding null hypothesis testing. BCCampus open publishing. Accessed April 16, 2024. https://opentextbc.ca/researchmethods/chapter/understanding-null-hypothesis-testing/#:~:text=In%20null%20hypothesis%20testing%2C%20this,said%20to%20be%20statistically%20significant  

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6.1: Developing Hypotheses

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Inferential statistics are used to test hypotheses. This is generally done by testing data from samples to learn what is likely true of populations. Hypothesis testing is central to behavioral sciences such as psychology. Before we can learn how to use inferential statistics to test hypotheses, we must first become familiar with two main things:

• The types of, and details surrounding, hypotheses, and
• The foundational concepts that connect and differentiate samples from populations.

Reviewing these two areas will provide the necessary foundation before we can embark on hypothesis testing.

Developing Hypotheses

Hypothesis testing is central to our work as researchers and statisticians. Two important skills to develop are the ability to generate testable hypotheses and the ability to correctly choose and use strategies to test those hypotheses. Researchers follow the scientific method by starting with making observations and reviewing existing knowledge. Therefore, researchers often have a general topic or question in mind and will then read existing, relevant research and theories to refine their question. When they have narrowed in, they will have a research question. As is overtly stated in the name, a research question is a question that a researcher or statistician intends to answer by analyzing data. When research is more exploratory in nature, the researcher may move forward solely with the research question to guide their work. However, scientific fields are aided by moving from research questions to hypotheses before planning for and collecting data. Research hypotheses are testable, expected answers to research questions that draw on larger theories, previous findings, and/or strong arguments. These forms of hypotheses can also be referred to as alternative hypotheses or simply as hypotheses. Designing studies, collecting data, and analyzing data depend upon the hypotheses that foment the research. Thus, inferential statistics and all the components that go along with it follow the formation and clear statement of a research hypothesis.

Stating a Research Hypothesis

Research hypotheses should be clear and specific, yet also succinct. A hypothesis should also be testable. If we state a hypothesis that is impossible to test, it forecloses any further investigation. To the contrary, a hypothesis should be what directs and demands investigation. In addition, a hypothesis should be directional, when possible. A directional hypothesis is one that includes information about the mathematical movement or difference that is expected; the direction tells which way you think the pattern(s) in the data will go. For example, if a researcher hypothesizes that teenagers and adults have different mean hours of sleep, their hypothesis is non-directional. This is because the hypothesis states a difference is anticipated

without specifying which group will have more or less sleep than the other. It could be that teenagers sleep more and adults sleep less or that teenagers sleep less and adults sleep more. In this example there are two opposing outcomes that could support the hypothesis. However, it is preferable to narrow the hypothesis down so that only one, specific outcome would support the hypothesis. If a researcher hypothesized that teenagers would sleep more hours than adults, their hypothesis would be directional. There is only one pattern in the data that could support this hypothesis: that the teens had comparatively more hours of sleep and adults had comparatively less sleep. Hypotheses such as these should be used whenever there is good reason to narrow in to one direction.

Whenever a hypothesis is stated, a hypothesis that counters it is also simultaneously being proposed which is known as a null hypothesis. A null hypothesis is a statement about a population that counters a research hypothesis and which is presumed to be true until there is sufficient evidence to refute or reject it. Because the null hypothesis is presumed to be true until there is sufficient evidence to support the research hypothesis and simultaneously reject the null hypothesis, research hypotheses are often called alternative hypotheses to reiterate that they are proposed alternatives to what is otherwise presumed to be true (which is the null hypothesis).

The assumption that the null hypothesis is true may seem counterintuitive at first as hypotheses are often grounded in theories and/or prior research, but there is an important reason for this: it requires that a researcher tests their presumptions (which are stated as their hypotheses) before they can present those presumptions as possible truths. This is what moves a field from being purely philosophical to empirical and, ultimately, scientific. Recall that a hypothesis should be testable. When a hypothesis is testable it means it is also falsifiable. Falsifiable means that something can be disproven or shown to be false if indeed it is not true. The onus is on the researcher to develop testable (and, thus, falsifiable) hypotheses and to test them before putting those hypotheses forth as possible facts. This process serves as an important filter between untested ideas (which can be stated as hypotheses) and supported contentions (hypotheses which have been supported by evidence).

Abbreviations and symbols are often used to state the null and alternative (i.e. research) hypotheses. Population symbols are used for the null hypothesis. An important property of alternative hypotheses is that they describe predicted values of population parameters (not sample statistics). The alternative hypothesis, therefore, can be written with the population symbols to indicate that the researcher expects the hypothesis to be true beyond the sample. However, the alternative hypothesis can also be written with sample symbols to reiterate that the data used to test it are from samples and can only be used to estimate the population. This is because one of the principles of hypothesis testing is that we determine the sample statistics in order to infer the population parameters. Thus, sample symbols are sometimes used for alternative hypotheses to emphasize the distinction between what is estimated through the use of sample data from what is true about populations.

The name “alternative hypothesis” can be abbreviated with the symbols \(H_a\) where the \(H\) stands for the word “hypothesis” and the subscript a abbreviates the word “alternative.” However, it is common for researchers to test more than one hypothesis in a single study. When doing so, it would be confusing to list several hypotheses with the same symbols. Therefore, it is also appropriate to enumerate the hypotheses in the order in which they will be tested using consecutive numbers in place of a in the subscript. Thus, \(H_1\) would be used as the abbreviation for the first hypothesis, \(H_2\) for the second hypothesis, \(H_3\) for the third hypothesis, and so on until each alternative hypothesis has been specified.

The null hypothesis is abbreviated with the symbols \(H_0\) because zero is synonymous with the word null. When a researcher states an alternative hypothesis, the null hypothesis is presumed and typically does not need to be overtly stated. Thus, null hypotheses are often all referred to simply as \(H_0\) without additional enumeration when they are written because they will be presented alongside their corresponding alternative hypothesis, if presented at all.

However, sometimes a researcher will overtly state both the alternative hypothesis and its corresponding null hypothesis (especially when they are taking a class and first learning how alternative and null hypotheses work). The researcher also makes the decision about whether the alternative hypothesis will be directional or non-directional based on information obtained from a review of prior research and theories. The alternative and null hypotheses for a given research question are mutually exclusive. Mutually exclusive means that if one of these two forms of hypothesis is true, the other one must be false. For example, only one of the following hypotheses in each pair can be true:

• Directional, alternative hypothesis: Last-minute studying will increase students' understanding of inferential statistics.
• Null hypothesis: Last-minute studying will not increase students' understanding of inferential statistics.
• Non-directional, alternative hypothesis: Last-minute studying will have an effect on students' understanding of inferential statistics.
• Null hypothesis: Last-minute studying will have no effect on students' understanding of inferential statistics.

Data can only support one statement in each pair and refute the other because each pair of hypotheses (alternative and null) are mutually exclusive.

Research Hypothesis In Psychology: Types, & Examples

Saul McLeod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Learn about our Editorial Process

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

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A research hypothesis, in its plural form “hypotheses,” is a specific, testable prediction about the anticipated results of a study, established at its outset. It is a key component of the scientific method .

Hypotheses connect theory to data and guide the research process towards expanding scientific understanding

Some key points about hypotheses:

• A hypothesis expresses an expected pattern or relationship. It connects the variables under investigation.
• It is stated in clear, precise terms before any data collection or analysis occurs. This makes the hypothesis testable.
• A hypothesis must be falsifiable. It should be possible, even if unlikely in practice, to collect data that disconfirms rather than supports the hypothesis.
• Hypotheses guide research. Scientists design studies to explicitly evaluate hypotheses about how nature works.
• For a hypothesis to be valid, it must be testable against empirical evidence. The evidence can then confirm or disprove the testable predictions.
• Hypotheses are informed by background knowledge and observation, but go beyond what is already known to propose an explanation of how or why something occurs.

Predictions typically arise from a thorough knowledge of the research literature, curiosity about real-world problems or implications, and integrating this to advance theory. They build on existing literature while providing new insight.

Types of Research Hypotheses

Alternative hypothesis.

The research hypothesis is often called the alternative or experimental hypothesis in experimental research.

It typically suggests a potential relationship between two key variables: the independent variable, which the researcher manipulates, and the dependent variable, which is measured based on those changes.

The alternative hypothesis states a relationship exists between the two variables being studied (one variable affects the other).

A hypothesis is a testable statement or prediction about the relationship between two or more variables. It is a key component of the scientific method. Some key points about hypotheses:

• Important hypotheses lead to predictions that can be tested empirically. The evidence can then confirm or disprove the testable predictions.

In summary, a hypothesis is a precise, testable statement of what researchers expect to happen in a study and why. Hypotheses connect theory to data and guide the research process towards expanding scientific understanding.

An experimental hypothesis predicts what change(s) will occur in the dependent variable when the independent variable is manipulated.

It states that the results are not due to chance and are significant in supporting the theory being investigated.

The alternative hypothesis can be directional, indicating a specific direction of the effect, or non-directional, suggesting a difference without specifying its nature. It’s what researchers aim to support or demonstrate through their study.

Null Hypothesis

The null hypothesis states no relationship exists between the two variables being studied (one variable does not affect the other). There will be no changes in the dependent variable due to manipulating the independent variable.

It states results are due to chance and are not significant in supporting the idea being investigated.

The null hypothesis, positing no effect or relationship, is a foundational contrast to the research hypothesis in scientific inquiry. It establishes a baseline for statistical testing, promoting objectivity by initiating research from a neutral stance.

Many statistical methods are tailored to test the null hypothesis, determining the likelihood of observed results if no true effect exists.

This dual-hypothesis approach provides clarity, ensuring that research intentions are explicit, and fosters consistency across scientific studies, enhancing the standardization and interpretability of research outcomes.

Nondirectional Hypothesis

A non-directional hypothesis, also known as a two-tailed hypothesis, predicts that there is a difference or relationship between two variables but does not specify the direction of this relationship.

It merely indicates that a change or effect will occur without predicting which group will have higher or lower values.

For example, “There is a difference in performance between Group A and Group B” is a non-directional hypothesis.

Directional Hypothesis

A directional (one-tailed) hypothesis predicts the nature of the effect of the independent variable on the dependent variable. It predicts in which direction the change will take place. (i.e., greater, smaller, less, more)

It specifies whether one variable is greater, lesser, or different from another, rather than just indicating that there’s a difference without specifying its nature.

For example, “Exercise increases weight loss” is a directional hypothesis.

Falsifiability

The Falsification Principle, proposed by Karl Popper , is a way of demarcating science from non-science. It suggests that for a theory or hypothesis to be considered scientific, it must be testable and irrefutable.

Falsifiability emphasizes that scientific claims shouldn’t just be confirmable but should also have the potential to be proven wrong.

It means that there should exist some potential evidence or experiment that could prove the proposition false.

However many confirming instances exist for a theory, it only takes one counter observation to falsify it. For example, the hypothesis that “all swans are white,” can be falsified by observing a black swan.

For Popper, science should attempt to disprove a theory rather than attempt to continually provide evidence to support a research hypothesis.

Can a Hypothesis be Proven?

Hypotheses make probabilistic predictions. They state the expected outcome if a particular relationship exists. However, a study result supporting a hypothesis does not definitively prove it is true.

All studies have limitations. There may be unknown confounding factors or issues that limit the certainty of conclusions. Additional studies may yield different results.

In science, hypotheses can realistically only be supported with some degree of confidence, not proven. The process of science is to incrementally accumulate evidence for and against hypothesized relationships in an ongoing pursuit of better models and explanations that best fit the empirical data. But hypotheses remain open to revision and rejection if that is where the evidence leads.

• Disproving a hypothesis is definitive. Solid disconfirmatory evidence will falsify a hypothesis and require altering or discarding it based on the evidence.
• However, confirming evidence is always open to revision. Other explanations may account for the same results, and additional or contradictory evidence may emerge over time.

We can never 100% prove the alternative hypothesis. Instead, we see if we can disprove, or reject the null hypothesis.

If we reject the null hypothesis, this doesn’t mean that our alternative hypothesis is correct but does support the alternative/experimental hypothesis.

Upon analysis of the results, an alternative hypothesis can be rejected or supported, but it can never be proven to be correct. We must avoid any reference to results proving a theory as this implies 100% certainty, and there is always a chance that evidence may exist which could refute a theory.

How to Write a Hypothesis

• Identify variables . The researcher manipulates the independent variable and the dependent variable is the measured outcome.
• Operationalized the variables being investigated . Operationalization of a hypothesis refers to the process of making the variables physically measurable or testable, e.g. if you are about to study aggression, you might count the number of punches given by participants.
• Decide on a direction for your prediction . If there is evidence in the literature to support a specific effect of the independent variable on the dependent variable, write a directional (one-tailed) hypothesis. If there are limited or ambiguous findings in the literature regarding the effect of the independent variable on the dependent variable, write a non-directional (two-tailed) hypothesis.
• Make it Testable : Ensure your hypothesis can be tested through experimentation or observation. It should be possible to prove it false (principle of falsifiability).
• Clear & concise language . A strong hypothesis is concise (typically one to two sentences long), and formulated using clear and straightforward language, ensuring it’s easily understood and testable.

Consider a hypothesis many teachers might subscribe to: students work better on Monday morning than on Friday afternoon (IV=Day, DV= Standard of work).

Now, if we decide to study this by giving the same group of students a lesson on a Monday morning and a Friday afternoon and then measuring their immediate recall of the material covered in each session, we would end up with the following:

• The alternative hypothesis states that students will recall significantly more information on a Monday morning than on a Friday afternoon.
• The null hypothesis states that there will be no significant difference in the amount recalled on a Monday morning compared to a Friday afternoon. Any difference will be due to chance or confounding factors.

More Examples

• Memory : Participants exposed to classical music during study sessions will recall more items from a list than those who studied in silence.
• Social Psychology : Individuals who frequently engage in social media use will report higher levels of perceived social isolation compared to those who use it infrequently.
• Developmental Psychology : Children who engage in regular imaginative play have better problem-solving skills than those who don’t.
• Clinical Psychology : Cognitive-behavioral therapy will be more effective in reducing symptoms of anxiety over a 6-month period compared to traditional talk therapy.
• Cognitive Psychology : Individuals who multitask between various electronic devices will have shorter attention spans on focused tasks than those who single-task.
• Health Psychology : Patients who practice mindfulness meditation will experience lower levels of chronic pain compared to those who don’t meditate.
• Organizational Psychology : Employees in open-plan offices will report higher levels of stress than those in private offices.
• Behavioral Psychology : Rats rewarded with food after pressing a lever will press it more frequently than rats who receive no reward.

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Research: Articulating Questions, Generating Hypotheses, and Choosing Study Designs

Mary p tully.

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Address correspondence to: Dr Mary P Tully, Manchester Pharmacy School, University of Manchester, Oxford Road, Manchester M13 9PT UK, e-mail: [email protected]

INTRODUCTION

Articulating a clear and concise research question is fundamental to conducting a robust and useful research study. Although “getting stuck into” the data collection is the exciting part of research, this preparation stage is crucial. Clear and concise research questions are needed for a number of reasons. Initially, they are needed to enable you to search the literature effectively. They will allow you to write clear aims and generate hypotheses. They will also ensure that you can select the most appropriate research design for your study.

This paper begins by describing the process of articulating clear and concise research questions, assuming that you have minimal experience. It then describes how to choose research questions that should be answered and how to generate study aims and hypotheses from your questions. Finally, it describes briefly how your question will help you to decide on the research design and methods best suited to answering it.

TURNING CURIOSITY INTO QUESTIONS

A research question has been described as “the uncertainty that the investigator wants to resolve by performing her study” 1 or “a logical statement that progresses from what is known or believed to be true to that which is unknown and requires validation”. 2 Developing your question usually starts with having some general ideas about the areas within which you want to do your research. These might flow from your clinical work, for example. You might be interested in finding ways to improve the pharmaceutical care of patients on your wards. Alternatively, you might be interested in identifying the best antihypertensive agent for a particular subgroup of patients. Lipowski 2 described in detail how work as a practising pharmacist can be used to great advantage to generate interesting research questions and hence useful research studies. Ideas could come from questioning received wisdom within your clinical area or the rationale behind quick fixes or workarounds, or from wanting to improve the quality, safety, or efficiency of working practice.

Alternatively, your ideas could come from searching the literature to answer a query from a colleague. Perhaps you could not find a published answer to the question you were asked, and so you want to conduct some research yourself. However, just searching the literature to generate questions is not to be recommended for novices—the volume of material can feel totally overwhelming.

Use a research notebook, where you regularly write ideas for research questions as you think of them during your clinical practice or after reading other research papers. It has been said that the best way to have a great idea is to have lots of ideas and then choose the best. The same would apply to research questions!

When you first identify your area of research interest, it is likely to be either too narrow or too broad. Narrow questions (such as “How is drug X prescribed for patients with condition Y in my hospital?”) are usually of limited interest to anyone other than the researcher. Broad questions (such as “How can pharmacists provide better patient care?”) must be broken down into smaller, more manageable questions. If you are interested in how pharmacists can provide better care, for example, you might start to narrow that topic down to how pharmacists can provide better care for one condition (such as affective disorders) for a particular subgroup of patients (such as teenagers). Then you could focus it even further by considering a specific disorder (depression) and a particular type of service that pharmacists could provide (improving patient adherence). At this stage, you could write your research question as, for example, “What role, if any, can pharmacists play in improving adherence to fluoxetine used for depression in teenagers?”

TYPES OF RESEARCH QUESTIONS

Being able to consider the type of research question that you have generated is particularly useful when deciding what research methods to use. There are 3 broad categories of question: descriptive, relational, and causal.

Descriptive

One of the most basic types of question is designed to ask systematically whether a phenomenon exists. For example, we could ask “Do pharmacists ‘care’ when they deliver pharmaceutical care?” This research would initially define the key terms (i.e., describing what “pharmaceutical care” and “care” are), and then the study would set out to look for the existence of care at the same time as pharmaceutical care was being delivered.

When you know that a phenomenon exists, you can then ask description and/or classification questions. The answers to these types of questions involve describing the characteristics of the phenomenon or creating typologies of variable subtypes. In the study above, for example, you could investigate the characteristics of the “care” that pharmacists provide. Classifications usually use mutually exclusive categories, so that various subtypes of the variable will have an unambiguous category to which they can be assigned. For example, a question could be asked as to “what is a pharmacist intervention” and a definition and classification system developed for use in further research.

When seeking further detail about your phenomenon, you might ask questions about its composition. These questions necessitate deconstructing a phenomenon (such as a behaviour) into its component parts. Within hospital pharmacy practice, you might be interested in asking questions about the composition of a new behavioural intervention to improve patient adherence, for example, “What is the detailed process that the pharmacist implicitly follows during delivery of this new intervention?”

After you have described your phenomena, you may then be interested in asking questions about the relationships between several phenomena. If you work on a renal ward, for example, you may be interested in looking at the relationship between hemoglobin levels and renal function, so your question would look something like this: “Are hemoglobin levels related to level of renal function?” Alternatively, you may have a categorical variable such as grade of doctor and be interested in the differences between them with regard to prescribing errors, so your research question would be “Do junior doctors make more prescribing errors than senior doctors?” Relational questions could also be asked within qualitative research, where a detailed understanding of the nature of the relationship between, for example, the gender and career aspirations of clinical pharmacists could be sought.

Once you have described your phenomena and have identified a relationship between them, you could ask about the causes of that relationship. You may be interested to know whether an intervention or some other activity has caused a change in your variable, and your research question would be about causality. For example, you may be interested in asking, “Does captopril treatment reduce blood pressure?” Generally, however, if you ask a causality question about a medication or any other health care intervention, it ought to be rephrased as a causality–comparative question. Without comparing what happens in the presence of an intervention with what happens in the absence of the intervention, it is impossible to attribute causality to the intervention. Although a causality question would usually be answered using a comparative research design, asking a causality–comparative question makes the research design much more explicit. So the above question could be rephrased as, “Is captopril better than placebo at reducing blood pressure?”

The acronym PICO has been used to describe the components of well-crafted causality–comparative research questions. 3 The letters in this acronym stand for Population, Intervention, Comparison, and Outcome. They remind the researcher that the research question should specify the type of participant to be recruited, the type of exposure involved, the type of control group with which participants are to be compared, and the type of outcome to be measured. Using the PICO approach, the above research question could be written as “Does captopril [ intervention ] decrease rates of cardiovascular events [ outcome ] in patients with essential hypertension [ population ] compared with patients receiving no treatment [ comparison ]?”

DECIDING WHETHER TO ANSWER A RESEARCH QUESTION

Just because a question can be asked does not mean that it needs to be answered. Not all research questions deserve to have time spent on them. One useful set of criteria is to ask whether your research question is feasible, interesting, novel, ethical, and relevant. 1 The need for research to be ethical will be covered in a later paper in the series, so is not discussed here. The literature review is crucial to finding out whether the research question fulfils the remaining 4 criteria.

Conducting a comprehensive literature review will allow you to find out what is already known about the subject and any gaps that need further exploration. You may find that your research question has already been answered. However, that does not mean that you should abandon the question altogether. It may be necessary to confirm those findings using an alternative method or to translate them to another setting. If your research question has no novelty, however, and is not interesting or relevant to your peers or potential funders, you are probably better finding an alternative.

The literature will also help you learn about the research designs and methods that have been used previously and hence to decide whether your potential study is feasible. As a novice researcher, it is particularly important to ask if your planned study is feasible for you to conduct. Do you or your collaborators have the necessary technical expertise? Do you have the other resources that will be needed? If you are just starting out with research, it is likely that you will have a limited budget, in terms of both time and money. Therefore, even if the question is novel, interesting, and relevant, it may not be one that is feasible for you to answer.

GENERATING AIMS AND HYPOTHESES

All research studies should have at least one research question, and they should also have at least one aim. As a rule of thumb, a small research study should not have more than 2 aims as an absolute maximum. The aim of the study is a broad statement of intention and aspiration; it is the overall goal that you intend to achieve. The wording of this broad statement of intent is derived from the research question. If it is a descriptive research question, the aim will be, for example, “to investigate” or “to explore”. If it is a relational research question, then the aim should state the phenomena being correlated, such as “to ascertain the impact of gender on career aspirations”. If it is a causal research question, then the aim should include the direction of the relationship being tested, such as “to investigate whether captopril decreases rates of cardiovascular events in patients with essential hypertension, relative to patients receiving no treatment”.

The hypothesis is a tentative prediction of the nature and direction of relationships between sets of data, phrased as a declarative statement. Therefore, hypotheses are really only required for studies that address relational or causal research questions. For the study above, the hypothesis being tested would be “Captopril decreases rates of cardiovascular events in patients with essential hypertension, relative to patients receiving no treatment”. Studies that seek to answer descriptive research questions do not test hypotheses, but they can be used for hypothesis generation. Those hypotheses would then be tested in subsequent studies.

CHOOSING THE STUDY DESIGN

The research question is paramount in deciding what research design and methods you are going to use. There are no inherently bad research designs. The rightness or wrongness of the decision about the research design is based simply on whether it is suitable for answering the research question that you have posed.

It is possible to select completely the wrong research design to answer a specific question. For example, you may want to answer one of the research questions outlined above: “Do pharmacists ‘care’ when they deliver pharmaceutical care?” Although a randomized controlled study is considered by many as a “gold standard” research design, such a study would just not be capable of generating data to answer the question posed. Similarly, if your question was, “Is captopril better than placebo at reducing blood pressure?”, conducting a series of in-depth qualitative interviews would be equally incapable of generating the necessary data. However, if these designs are swapped around, we have 2 combinations (pharmaceutical care investigated using interviews; captopril investigated using a randomized controlled study) that are more likely to produce robust answers to the questions.

The language of the research question can be helpful in deciding what research design and methods to use. Subsequent papers in this series will cover these topics in detail. For example, if the question starts with “how many” or “how often”, it is probably a descriptive question to assess the prevalence or incidence of a phenomenon. An epidemiological research design would be appropriate, perhaps using a postal survey or structured interviews to collect the data. If the question starts with “why” or “how”, then it is a descriptive question to gain an in-depth understanding of a phenomenon. A qualitative research design, using in-depth interviews or focus groups, would collect the data needed. Finally, the term “what is the impact of” suggests a causal question, which would require comparison of data collected with and without the intervention (i.e., a before–after or randomized controlled study).

CONCLUSIONS

This paper has briefly outlined how to articulate research questions, formulate your aims, and choose your research methods. It is crucial to realize that articulating a good research question involves considerable iteration through the stages described above. It is very common that the first research question generated bears little resemblance to the final question used in the study. The language is changed several times, for example, because the first question turned out not to be feasible and the second question was a descriptive question when what was really wanted was a causality question. The books listed in the “Further Reading” section provide greater detail on the material described here, as well as a wealth of other information to ensure that your first foray into conducting research is successful.

This article is the second in the CJHP Research Primer Series, an initiative of the CJHP Editorial Board and the CSHP Research Committee. The planned 2-year series is intended to appeal to relatively inexperienced researchers, with the goal of building research capacity among practising pharmacists. The articles, presenting simple but rigorous guidance to encourage and support novice researchers, are being solicited from authors with appropriate expertise.

Previous article in this series:

Bond CM. The research jigsaw: how to get started. Can J Hosp Pharm . 2014;67(1):28–30.

Competing interests: Mary Tully has received personal fees from the UK Renal Pharmacy Group to present a conference workshop on writing research questions and nonfinancial support (in the form of travel and accommodation) from the Dubai International Pharmaceuticals and Technologies Conference and Exhibition (DUPHAT) to present a workshop on conducting pharmacy practice research.

• 1. Hulley S, Cummings S, Browner W, Grady D, Newman T. Designing clinical research. 4th ed. Philadelphia (PA): Lippincott, Williams and Wilkins; 2013. [ Google Scholar ]
• 2. Lipowski EE. Developing great research questions. Am J Health Syst Pharm. 2008;65(17):1667–70. doi: 10.2146/ajhp070276. [ DOI ] [ PubMed ] [ Google Scholar ]
• 3. Richardson WS, Wilson MC, Nishikawa J, Hayward RS. The well-built clinical question: a key to evidence-based decisions. ACP J Club. 1995;123(3):A12–3. [ PubMed ] [ Google Scholar ]

Further Reading

• Cresswell J. Research design: qualitative, quantitative and mixed methods approaches. London (UK): Sage; 2009. [ Google Scholar ]
• Haynes RB, Sackett DL, Guyatt GH, Tugwell P. Clinical epidemiology: how to do clinical practice research. 3rd ed. Philadelphia (PA): Lippincott, Williams & Wilkins; 2006. [ Google Scholar ]
• Kumar R. Research methodology: a step-by-step guide for beginners. 3rd ed. London (UK): Sage; 2010. [ Google Scholar ]
• Smith FJ. Conducting your pharmacy practice research project. London (UK): Pharmaceutical Press; 2005. [ Google Scholar ]
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How To Write A Research Paper

How To Write A Hypothesis

How To Write a Hypothesis in a Research Paper | Steps & Examples

13 min read

Published on: Aug 5, 2021

Last updated on: Mar 5, 2024

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Imagine spending hours conducting experiments, only to realize that your hypothesis is unclear or poorly constructed.

This can lead to wasted time, resources, and a lack of meaningful results.

Fortunately, by mastering the art of hypothesis writing, you can ensure that your research paper is focused and structured. 

This comprehensive guide will provide you with step-by-step instructions and examples to write a hypothesis effectively.

By the end of this guide, you will have all the knowledge to write hypotheses that drive impactful scientific research.

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What is a Hypothesis?

A hypothesis is a tentative explanation or prediction that can be tested through scientific investigation. 

It is like a roadmap that guides researchers in their quest for answers. By formulating a hypothesis, researchers make educated guesses about the relationship between variables or phenomena.

Think of a hypothesis as a detective's hunch. Just like a detective forms a theory about a crime based on evidence, a researcher develops a hypothesis based on existing knowledge and observations. 

Now that we have a basic understanding of what a hypothesis is, let's delve into the process of writing one effectively.

Variables in Hypothesis

In hypotheses, variables play a crucial role as they represent the factors that are being studied and tested. 

Let's explore two types of variables commonly found in hypotheses:

1. Independent Variable: This variable is manipulated or controlled by the researcher. It is the factor believed to have an effect on the dependent variable. Here's an example:

Hypothesis: "Increasing study time (independent variable) leads to improved test scores (dependent variable) in students."

In this hypothesis, the independent variable is the study time, which the researcher can manipulate to observe its impact on the test scores.

2. Dependent Variable: This variable is the outcome or response that is measured or observed as a result of the changes in the independent variable. Here's an example:

Hypothesis: "Exposure to sunlight (independent variable) affects plant growth (dependent variable)."

In this hypothesis, the dependent variable is plant growth, which is expected to be influenced by the independent variable, sunlight exposure. The researcher measures or observes the changes in plant growth based on the different levels of sunlight exposure.

Research Question vs Hypothesis

A research question is an inquiry that defines the focus and direction of a research study. A hypothesis, on the other hand, is a tentative statement that suggests a relationship between variables or predicts the outcome of a research study.

Hypothesis vs. Prediction

The difference between a hypothesis and a prediction is slight, but it's critical to understand. 

Hypotheses are a great way to explain why something happens based on scientific methods. A prediction is a statement that says something will happen based on what has been observed.

A hypothesis is a statement with variables. A prediction is a statement that says what will happen in the future.

Theory vs. Hypothesis

The theory and hypothesis have some differences between them.

• A hypothesis is the explanation of a phenomenon that will be supported through scientific methods. 
• A theory is a well-substantiated and already-tested explanation backed by evidence.  

To turn a hypothesis into a theory, you need to test it in different situations and with strong evidence. Theories can also be used to make predictions about something that is not understood. Once you have predictions, you can turn them into hypotheses that can be tested.

How to Develop a Hypothesis Step by Step?

Developing a hypothesis is an important step in scientific research, as it sets the foundation for designing experiments and testing theories. 

Let's explore the step-by-step process of developing a hypothesis, using the example of studying the effects of exercise on sleep quality.

Step 1. Ask a Question

To begin, ask a specific question that focuses on the relationship between variables. In our example, the question could be: "Does regular exercise have a positive impact on sleep quality?"

Step 2. Do Background Research

Before formulating your hypothesis, conduct preliminary research to gather existing knowledge on the topic. 

Review scientific studies, articles, and relevant literature to understand the current understanding of exercise and its potential effects on sleep quality. This research will provide a foundation for formulating your hypothesis.

Step 3. Develop Your Hypothesis

Based on your question and preliminary research, formulate a hypothesis that predicts the expected relationship between variables. In our example, the hypothesis could be: 

"Regular exercise has a positive influence on sleep quality, resulting in improved sleep duration and reduced sleep disturbances."

Step 4. Refine Your Hypothesis

Refine your hypothesis by making it more specific and testable. Specify the variables involved and the anticipated outcomes in clear terms. For instance: 

"Engaging in moderate-intensity aerobic exercise for at least 30 minutes, three times a week, will lead to an increase in total sleep time and a decrease in the frequency of sleep disruptions."

Step 5. Express Your Hypothesis in Three Forms

To ensure comprehensiveness, phrase your hypothesis in three different ways: as a simple statement, as a positive correlation, and as a negative correlation. This will cover different perspectives and potential outcomes. 

Using our example:

• Simple Statement: "Regular exercise positively affects sleep quality."
• Positive Correlation: "As the frequency of regular exercise increases, sleep quality improves."
• Negative Correlation: "A lack of regular exercise is associated with poorer sleep quality."

Step 6. Construct a Null Hypothesis

In addition to the main hypothesis, it is important to write a null hypothesis. The null hypothesis assumes that there is no significant relationship between the variables being studied. 

The example below shows how to state the null hypothesis in a research paper: 

By following these steps, you can develop a well-structured and testable hypothesis that serves as a guiding framework for your scientific research.

Types of Research Hypotheses with Examples

Hypotheses come in various forms, depending on the nature of the research and the relationship between variables. 

Here are seven common types of hypotheses along with examples:

• Simple Hypothesis: A straightforward statement about the expected relationship between variables.

Example: "Increasing fertilizer dosage will lead to higher crop yields."

• Complex Hypothesis: A hypothesis that suggests a more intricate relationship between multiple variables.

Example: "The interaction of genetic factors and environmental stressors contributes to the development of certain mental disorders."

• Directional Hypothesis: A hypothesis that predicts the specific direction of the relationship between variables.

Example: "As temperature decreases, the viscosity of the liquid will increase."

• Non-Directional Hypothesis: A hypothesis that suggests a relationship between variables without specifying the direction.

Example: "There is a correlation between caffeine consumption and anxiety levels."

• Null Hypothesis: A hypothesis that assumes no significant relationship between variables.

Example: "There is no difference in exam performance between students who study in silence and students who listen to music."

• Alternative Hypothesis: A hypothesis that contradicts or offers an alternative explanation to the null hypothesis.

Example: "There is a significant difference in weight loss between individuals following a low-carb diet and those following a low-fat diet."

• Associative Hypothesis: A hypothesis that suggests a relationship between variables without implying causality.

Example: "There is a correlation between exercise frequency and cardiovascular health."

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What Makes a Good Hypothesis? 5 Key Elements

Crafting a good hypothesis is essential for conducting effective scientific research. A well-formed hypothesis sets the stage for meaningful experiments. 

Here are some key characteristics that make a hypothesis strong:

1. Testable and Specific

A good hypothesis should be testable through observation or experimentation. It should be formulated in a way that allows researchers to gather data and evidence to support or refute it. 

When writing a research hypothesis, it is crucial to structure it in a manner that suggests clear ways to measure or observe the variables involved.

2. Grounded in Existing Knowledge

A strong hypothesis is built upon a foundation of existing knowledge and understanding of the topic. By connecting your hypothesis to previous findings, you ensure that your research contributes to the broader scientific knowledge. 

This incorporation of existing knowledge aligns with the concept of research hypotheses, where hypotheses are framed based on the understanding of the subject from previous studies.

3. Falsifiable

A good hypothesis must be falsifiable, meaning that it can be proven false if it is indeed false. This principle is important because it allows for rigorous testing and prevents researchers from making claims that are impossible to verify or disprove. 

This aligns with the idea of statistical hypothesis, where hypotheses need to be formulated in a way that allows statistical testing to determine their validity.

4. Clearly Defines Variables

A well-formulated hypothesis clearly identifies the independent and dependent variables involved in the research. It specifies the relationship between two variables and states what researchers expect to find during the study. 

The clarity in defining variables is a crucial aspect of developing logical hypotheses.

5. Supported by Logic and Reasoning

A good hypothesis is logical and based on sound reasoning. It should be supported by evidence and a plausible rationale. The relationship between two variables proposed in the hypothesis should be grounded in a solid understanding of cause-and-effect relationships and theories.

A strong hypothesis, whether it is a research hypothesis, statistical hypothesis, or logical hypothesis, encompasses these key elements. By incorporating these elements you lay the groundwork for a robust and meaningful research study.

Hypothesis Examples 

Here are a few more examples for you to look at and get a better understanding!

How to Write a Hypothesis in Research

Research Question: "Does exposure to violent video games increase aggressive behavior in adolescents?"

Hypothesis 1: "Adolescents who are exposed to violent video games will display higher levels of aggressive behavior compared to those who are not exposed."

Hypothesis 2: "There is a positive correlation between the amount of time spent playing violent video games and the level of aggressive behavior exhibited by adolescents."

How to Write a Hypothesis for a Lab Report:

Lab Experiment: Testing the effect of different fertilizers on plant growth.

Hypothesis 1: "Plants treated with fertilizer A will exhibit greater growth in terms of height and leaf count compared to plants treated with fertilizer B."

Hypothesis 2: "There is a significant difference in the growth rate of plants when exposed to different types of fertilizers."

How to Write a Hypothesis in a Report:

Report Topic: Investigating the impact of social media usage on self-esteem.

Hypothesis 1: "Individuals who spend more time on social media will report lower levels of self-esteem compared to those who spend less time on social media."

Hypothesis 2: "There is an inverse relationship between the frequency of social media use and self-esteem levels among individuals."

Example of Hypothesis in a Research Proposal:

Crafting hypotheses in a research proposal is pivotal for outlining the research aims and guiding the investigative process. Here's an example of a hypothesis within a research proposal:

Research Proposal Topic: Investigating the impact of social media usage on adolescents' self-esteem levels.

Hypothesis: "Adolescents who spend more time on social media platforms will have lower self-esteem levels compared to those who spend less time on social media."

How To Write a Hypothesis Psychology

Research Topic: Investigating the impact of mindfulness meditation on reducing symptoms of anxiety in college students.

Hypothesis 1: "College students who regularly practice mindfulness meditation will report lower levels of anxiety compared to those who do not engage in mindfulness practices."

Hypothesis 2: "There will be a significant decrease in anxiety scores among college students who undergo a structured mindfulness meditation program compared to a control group receiving no intervention."

How to Write a Hypothesis for a Research Paper:

 Research Paper Topic: Examining the effect of mindfulness meditation on stress reduction.

Hypothesis 1: "Participating in regular mindfulness meditation practice will result in a significant decrease in perceived stress levels among participants."

Hypothesis 2: "There is a positive association between the frequency of mindfulness meditation practice and the reduction of stress levels in individuals."

How to Write a Hypothesis for Qualitative Research:

Qualitative Research Topic: Exploring the experiences of first-time mothers during the postpartum period.

Hypothesis 1: "First-time mothers will report feelings of increased anxiety and stress during the early weeks of the postpartum period."

Hypothesis 2: "There will be a common theme of adjustment challenges among first-time mothers in their narratives about the postpartum experience."

Good and Bad Hypothesis Example

Below are examples of good and bad hypotheses, along with their corresponding research question and hypothesis examples:

In conclusion, a well-crafted hypothesis sets the stage for designing experiments, collecting data, and drawing meaningful conclusions. 

By following the steps of formulating a hypothesis, researchers can ensure that their investigations are grounded in solid reasoning. AI essay writing tools can be a great help in getting ideas.

However, If you need assistance with essay writing, consider leveraging the services of CollegeEssay.org. Our team of experienced writers is dedicated to delivering high-quality, customized essays that meet your requirements and deadlines. 

Don't hesitate to visit CollegeEssay.org and benefit from our professional essay writing service . Contact us today and say goodbye to your academic paper-writing worries.

Frequently Asked Questions

What are the 3 required parts of a hypothesis.

The three main parts of the hypothesis are: 

• Problem 
• Proposed solution 
• Result 

What are 5 characteristics of a good hypothesis?

The main five characteristics of a good hypothesis are: 

• Clarity 
• Relevant to problem 
• Consistency 
• Specific 
• Testability 

What should not be characteristic of a hypothesis?

Complexity should not be a good characteristic of a hypothesis. 

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Hypothesis: Basic Research Guidelines & Examples

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A hypothesis refers to a simple statement that predicts the findings of a research study. Basically, researchers develop propositions to provide tentative answers to research questions that address different aspects of a study objective. In writing, a scholar must use existing theories and knowledge to create a valid assumption. Besides, a researcher focuses on testing supposed claims through different methods, like experiments, observations, and statistical analysis of obtained data. In practice, the findings from a study can either support or refute a premise under examination. Then, when writing a suggestion, scholars should conduct adequate research on a specific topic, brainstorm for ideas, draft an assertion, revise a draft claim, and write a final sentence in simple language. Moreover, these steps lead to a valid development of accurate and precise propositions that identify relationships between independent and dependent variables. In practice, one should rely on a cause-and-effect theory when developing a hypothesis.

General Aspects

A good hypothesis suggests a sentence as a statement that gives a particular prediction about the findings of a research study. Basically, people make a specific hypothesis, which acts as a tentative answer to a research question. However, a proposition may lack scientific or scholarly proof. Then, a reasonable claim must address different aspects of a question under analysis. In writing, people must base their propositions on existing theories and knowledge. Besides, such a statement has to be testable through various methods, like experiments, observations, and statistical analysis. In practice, the findings from a study can either support or refute a working thesis. Therefore, writing a study assumption refers to a simple and clear statement that tries to predict the results of research.

What Is a Hypothesis and Its Purpose

According to its definition, a hypothesis is a testable statement or prediction about a specific phenomenon or a relationship between two or more variables, forming a unique basis for scientific investigation. In principle, such a statement is formulated based on observations, existing knowledge, and theoretical frameworks. For example, the main purpose of writing a hypothesis is to establish a specific direction for a particular study, enabling researchers to design experiments and collect data in a structured manner (Reichardt, 2022). Moreover, by testing a defined assertion through experimentation and analysis, people can determine whether their predictions hold true, contributing to a broader understanding of a discussed topic. This process of hypothesis testing is fundamental to a scientific method, as it allows for a particular validation, refinement, or rejection of theoretical concepts (Dillard & Flenner, 2021). In turn, the length of a hypothesis depends on academic levels and scopes of research, while general writing guidelines are:

High School

• Length: 1 sentence
• Word Count: 10-15 words
• Detail: A simple, clear, and testable statement about a specific relationship between variables.
• Example: “If plants are watered with different types of liquids, then the growth rate will vary.”

College (Undergraduate)

• Word Count: 15-30 words
• Detail: More detailed, specifying defined variables and expected outcomes with writing some contextual background.
• Example: “Students who study in a quiet environment will perform better on exams than those who study in a noisy environment due to fewer distractions and improved concentration.”

University (Advanced Undergraduate or Honors Thesis)

• Word Count: 20-35 words
• Detail: Includes specific variables, a rationale based on preliminary research, and a clear expected outcome.
• Example: “Exposure to natural light in the workplace will increase employee productivity compared to artificial lighting, as natural light has been shown to improve mood and energy levels.”

Master’s Thesis

• Length: 1-2 sentences
• Word Count: 25-40 words
• Detail: Detailed and precise writing, including variables, expected relationship, and grounding in existing literature or theoretical framework.
• Example: “Implementing a flipped classroom model in undergraduate biology courses will result in higher student engagement and academic performance, as this model promotes active learning and individualized instruction, which have been positively correlated with student outcomes in previous studies.”

Ph.D. Dissertation

• Length: 2-4 sentences (or more, if necessary)
• Word Count: 30-70+ words
• Detail: Highly detailed, specifying complex relationships between multiple variables, grounded in extensive literature review and theoretical framework, with writing about clear and expected outcomes.
• Example: “Incorporating machine learning algorithms into predictive models for climate change will significantly improve an overall accuracy of long-term weather forecasts. This assumption is based on a premise that machine learning can identify innovative patterns in large datasets that traditional statistical methods may miss, thus providing more reliable predictions of climatic phenomena.”

Note: Some writing components of a hypothesis can be added, deleted, or combined with each other, and such a statement is usually 1 sentence long. For example, the three main parts of a hypothesis statement are an independent variable, a dependent variable, and a predicted relationship between them (Lund, 2021). In a research paper, a standard hypothesis is typically found in an introduction section, where such a statement outlines an expected relationship between variables and sets a particular stage for an entire study. Further on, a hypothesis is a testable prediction about a unique relationship between variables, while a research question is a broad query that guides an entire investigation into a specific topic (Misra et al., 2021). Moreover, there is a direct relationship between a hypothesis and research objectives, as the former provides a specific, testable prediction that aligns with and helps to achieve broader goals outlined by the latter. In writing, a basic checklist to evaluate an overall effectiveness of any hypothesis includes ensuring a research assertion is a clear, specific, and testable statement that is based on existing knowledge and covers both independent and dependent variables (Rubin & Donkin, 2022). Finally, to start a hypothesis, people begin by writing an “If” statement that clearly identifies an independent variable, followed by a “then” statement predicting a specific outcome or effect on a dependent variable.

Independent and Dependent Variables

A hypothesis in some studies must contain independent and dependent variables. Basically, hypothesis testing is a statistical method that people use to determine a specific connection between suggestions and their alternative outcomes to understand what is true or not and write about them. For example. experimental and correlational studies examine relationships between two or more variables (Sharang, 2020). In turn, independent elements refer to factors people can control or change. Besides, this aspect refers to factors scholars observe or measure for their writing. Then, a null hypothesis of experimental and correlational studies must predict relationships between dependent and independent variables. Moreover, such predictions should not be guesses but should contain evidence from research studies.

There are different types of hypotheses people can develop for writing their studies. In this case, common types of hypotheses include:

• A simple hypothesis refers to predictions of relationships between independent and dependent variables.
• A complex hypothesis predicts relationships between two or more independent and dependent variables.
• An empirical hypothesis is a working prediction that exists when a person tests a specific theory by using observations and experiments. Basically, this type of assertion goes through some trial and error methods to obtain the necessary findings and write about them. In some instances, people may change some aspects around other elements.
• A null hypothesis , denoted as H 0 , exists when a person believes a relationship does not exist between independent and dependent variables. Basically, this statement may exist when an individual lacks adequate information to make a scientific prediction. Besides, inferences made from the findings attempt to disapprove or discredit a null theory.
• An alternative hypothesis , denoted as H 1 , attempts to disapprove a null proposition. In this case, people attempt to discover or affirm an alternative proposition.
• A logical hypothesis refers to a proposed explanation of a concept that contains limited evidence. In writing, investigators intend to turn a reasonable assumption into an empirical claim. Besides, they put theories or postulate them to a particular testing process.
• A statistical hypothesis is a claim related to studies that examine a section of a specific population. In this case, people identify a sample population and study their behaviors related to a given research question. 

Steps on How to Write a Good Hypothesis

To write a good hypothesis, people clearly define specific independent and dependent variables and formulate a testable prediction about a particular relationship between them, often structured as an “If [independent variable], then [dependent variable]” statement. As such, researchers should focus on developing and writing reasonable assertation statements for their studies. For example, one should consider different factors that relate to existing studies or theories (Sharang, 2020). In writing, some predictions should pertain to research data and provide tentative answers to study questions. Hence, the following are essential writing steps a person should consider when developing a proposition.

Step 1: Researching

A first step in developing a hypothesis is to research and gather details related to writing an intended topic. Basically, researching allows a scholar to gain more knowledge concerning issues and factors and how variables change. For example, to form a hypothesis sentence, people start wording by identifying independent and dependent variables, reviewing existing literature, and then creating a clear, testable prediction that outlines an expected relationship between defined elements (Reichardt, 2022). Besides, this step will enable people to become familiar with the expected results. As a result, an entire writing process influences a relevant theory’s development.

Step 2: Asking Questions

A person should develop research questions before developing a main claim. For instance, investigators should create scientific questions that relate to studied and identified elements (Dillard & Flenner, 2021). In writing, brainstorming enhances a particular ability to determine relationships between independent and dependent variables. Basically, successful scholars remain focused on writing about one cause-and-effect theory to ensure they develop accurate ideas for a prediction. Therefore, a second writing step in developing a proposition is to brainstorm questions that reveal a specific relationship between independent and dependent elements. 

Step 3: Use Clear Language

Scholars should use simple and clear language when developing any suggestion for writing a study. For instance, one should draft concise predictions that answer developed research questions (Sharang, 2020). In practice, one should write a hypothesis in a particular form of a direct proposition that an action leads to a specific result. Futher on, the three main words that should be in a hypothesis statement are “if,” “then,” and “because.” Moreover, a person should not state a supposition as a question but as an affirmative statement that predicts outcomes from a particular course of action. Therefore, a third step in developing a new theory involves selecting a simple language for writing scientific predictions. 

Step 4. Revising a Statement

A scholar should revise a draft hypothesis to ensure writing any prediction makes a testable thesis through research and experimentation. For instance, a person should review a prediction to ensure such a sentence captures relationships between at least two elements (Dillard & Flenner, 2021). Hence, a scholar must revise a drafted proposition to ensure this statement captures a testable relationship between independent and dependent variables. In writing, some examples of sentence starters for beginning a hypothesis statement are:

• If [independent variable] is introduced or modified, then we anticipate [dependent variable] will exhibit a measurable change in terms of … .
• It is hypothesized that a particular presence or alteration of [independent element] will significantly affect [dependent element] by causing … .
• We predict that variations in [independent aspect] will result in corresponding changes in [dependent aspect], specifically in key aspects of … .
• A formulated assumption posits that altering [independent variable] will lead to observable differences in [dependent variable], particularly in relation to … .
• Based on existing theories and previous research, it is expected that modifying [independent element] will impact [dependent element] by … .
• We hypothesize an increase or decrease in [independent aspect], which will have a direct influence on [dependent aspect], leading to … .
• It is proposed that a particular manipulation of [independent variable] will result in [specific outcome] within [dependent variable] due to a specific mechanism of … .
• If [independent element] is systematically varied, then [dependent element] will demonstrate a change characterized by … .
• A current premise suggests that specific changes in [independent aspect] will cause predictable alterations in [dependent aspect], which can be measured by … .
• We expect that, by introducing [independent variable], there will be a significant impact on [dependent variable], as evidenced by changes in … .

• Research question – How does divorce affect sociological development among young children?
• H 0 – Challenges that lead to divorce hurt young children’s social development, which affects their ability to interact with other people. 
• H 1 – Most children manage to cope with domestic challenges that lead to divorce, enabling them to realize healthy sociological development.
• Research question – How did tenebrism influence baroque art during the 16 th and 17 th centuries?
• H 0 – A particular origin of tenebrism had a positive impact on a dynamic appearance of baroque art.
• H 1 – Baroque art emerged as a unique art that did not have any form of external influence.
• Research question – To what extent does geological activity affect the Earth?
• H 0 – A specific movement of tectonic plates beneath the Earth’s surface results in volcanic eruptions and faults that lead to mountains and lift valleys.  
• H 1 – Mountains and valleys are natural features with little connection with geological activities like a particular movement of tectonic plates beneath the Earth’s surface.
• Research question – Do animals have rights and welfare in society?
• H 0 – Wild and domestic animals are living creatures with a right to care and protection by humans.
• H 1 – Wild and domestic animals are subordinate to humans, which implies they do not have a right to care and protection.  
• Research question – Does a specific consumption of genetically modified plants cause health complications in humans?
• H 0 – Genetically modified foods are safe for human consumption and do not pose any possible health risks.
• H 1 – Genetically modified foods interfere with healthy cell development, which leads to health complications.

Indigenous Studies

• Research question – What role does culture play among Indigenous communities?
• H 0 – Cultural practices among Aboriginals promote their identity and contribute to the members’ overall well-being.
• H 1 – cultural practices among Aboriginals do not significantly contribute to an overall quality of their lives.
• Research question – Does fascism exist in the twenty-first century?
• H 0 – Established forms of democracy in the twenty-first century do not allow political leaders to implement all the fascism elements.
• H 1 – Some political leaders in the twenty-first century adopt radical policies that promote a particular existence of fascism.
• Research question – Do neutrons have mass?
• H 0 – Neutrons are small particles that have masses.
• H 1 – Neutrons are small particles whose weight remains insignificant.

Health Studies

• Research question – How do evidence-based treatment approaches enhance an overall quality of current treatments?
• H 0 – Evidence-based treatment methods allow doctors to gather adequate and accurate information about patients, which helps them to tailor treatment and care approaches to meet people’s needs.
• H 1 – Evidence-based approaches do not enhance an overall quality of current treatments since they lead to inconsistency in the care and medications given to a patient.

Environmental Studies

• Research question – To what extent do human activities contribute to global warming?
• H 0 – Most human activities release greenhouse gases into the atmosphere, which results in a particular rise in average temperatures.
• H 1 – Most human activities release insignificant amounts of greenhouse gases into the atmosphere, contributing to global warming.

What to Include

Common mistakes.

• Being Too Vague: A hypothesis statement must be specific and clearly define corresponding variables and expected outcomes.
• Not Being Testable: A prediction should be formulated in a way that can be empirically tested through experiments or observations.
• Lack of Clarity: Avoid writing in ambiguous language since a scientific assertion should be clear and straightforward.
• Being Too Complex: Keep a statement focused on a single relationship between variables to avoid confusion.
• Ignoring Prior Research: Writing a good premise is based on existing knowledge and theories, while ignoring these concepts can lead to redundant or invalid studies.
• Using Subjective Terms: Avoid writing terms that are open to interpretation because any prediction should be objective and measurable.
• Making Assumptions: Do not assume outcomes without evidence since any assertion should be based on logical reasoning.
• Not Aligning With a Research Question: Ensure a formulated prediction directly addresses a study question posed.
• Being Too Broad: Writing a hypothesis statement should be narrow enough to be manageable within a specific scope of research.
• Neglecting to Include Variables: Clearly identify and define both independent and dependent variables in a given assertion.

Writing Tips

In its simple definition, a basic hypothesis gives a specific prediction about the findings of a research paper or study. Basically, people develop scientific predictions to provide tentative answers to study questions (Reichardt, 2022). In turn, some of the factors one must consider when writing an assumption statement include:

• conduct adequate research on a specific topic;
• brainstorm for ideas;
• draft a statement;
• revise a draft proposition;
• write a final assertion in simple language.

A hypothesis is a statement predicting a specific outcome of a research study, which is based on existing theories, literature, and knowledge. Basically, writing such a statement includes independent and dependent variables and must be testable through experiments, observations, or statistical analysis. Further on, common types of hypotheses include simple, complex, empirical, null, alternative, logical, and statistical writing formats. To develop a good hypothesis, one should research a specific topic, ask relevant questions, use clear language, and revise a formulated statement to ensure its writing captures a direct relationship between variables. Finally, accurate assumptions help in identifying cause-and-effect relationships in research.

Dillard, A., & Flenner, J. (2021). Crush hypothesis testing . Happy Hypotenuse Publishing.

Lund, T. (2021). Research problems and hypotheses in empirical research. Scandinavian Journal of Educational Research , 66 (7), 1183–1193. https://doi.org/10.1080/00313831.2021.1982765

Misra, D. P., Gasparyan, A. Y., Zimba, O., Yessirkepov, M., Agarwal, V., & Kitas, G. D. (2021). Formulating hypotheses for different study designs. Journal of Korean Medical Science , 36 (50), 1–9. https://doi.org/10.3346/jkms.2021.36.e338

Reichardt, C. S. (2022). The method of multiple hypotheses: A guide for professional and academic researchers . Routledge, Taylor & Francis Group.

Rubin, M., & Donkin, C. (2022). Exploratory hypothesis tests can be more compelling than confirmatory hypothesis tests. Philosophical Psychology , 1–29. https://doi.org/10.1080/09515089.2022.2113771

Sharang, S. (2020). Research methodology techniques: Understanding how to write, present and defend any research report . Stephen Sharang.

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Statistics > Machine Learning

Title: on the sparsity of the strong lottery ticket hypothesis.

Abstract: Considerable research efforts have recently been made to show that a random neural network $N$ contains subnetworks capable of accurately approximating any given neural network that is sufficiently smaller than $N$, without any training. This line of research, known as the Strong Lottery Ticket Hypothesis (SLTH), was originally motivated by the weaker Lottery Ticket Hypothesis, which states that a sufficiently large random neural network $N$ contains \emph{sparse} subnetworks that can be trained efficiently to achieve performance comparable to that of training the entire network $N$. Despite its original motivation, results on the SLTH have so far not provided any guarantee on the size of subnetworks. Such limitation is due to the nature of the main technical tool leveraged by these results, the Random Subset Sum (RSS) Problem. Informally, the RSS Problem asks how large a random i.i.d. sample $\Omega$ should be so that we are able to approximate any number in $[-1,1]$, up to an error of $ \epsilon$, as the sum of a suitable subset of $\Omega$. We provide the first proof of the SLTH in classical settings, such as dense and equivariant networks, with guarantees on the sparsity of the subnetworks. Central to our results, is the proof of an essentially tight bound on the Random Fixed-Size Subset Sum Problem (RFSS), a variant of the RSS Problem in which we only ask for subsets of a given size, which is of independent interest.

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