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How to Write an Effective Conclusion for a Science Lab Report

Last Updated: August 9, 2024 Fact Checked

• Discussing the Experiment
• Writing What You Learned
• Ending Your Conclusion

Finalizing Your Lab Report

This article was co-authored by Bess Ruff, MA . Bess Ruff is a Geography PhD student at Florida State University. She received her MA in Environmental Science and Management from the University of California, Santa Barbara in 2016. She has conducted survey work for marine spatial planning projects in the Caribbean and provided research support as a graduate fellow for the Sustainable Fisheries Group. There are 10 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 1,783,422 times.

A lab report describes an entire experiment from start to finish, outlining the procedures, reporting results, and analyzing data. The report is used to demonstrate what has been learned, and it will provide a way for other people to see your process for the experiment and understand how you arrived at your conclusions. The conclusion is an integral part of the report; this is the section that reiterates the experiment’s main findings and gives the reader an overview of the lab trial. Writing a solid conclusion to your lab report will demonstrate that you’ve effectively learned the objectives of your assignment.

How to Write a Lab Report Conclusion

• Restate the purpose of the experiment and your procedures.
• Describe the results or findings and if they support your hypothesis.
• Mention what you've learned from the experiment.
• Note any errors or uncertainties that could affect the results.
• Propose experiments for the future to gain more findings.

Outlining Your Conclusion

• Restate : Restate the lab experiment by describing the assignment.
• Explain : Explain the purpose of the lab experiment. What were you trying to figure out or discover? Talk briefly about the procedure you followed to complete the lab.
• Results : Explain your results. Confirm whether or not your hypothesis was supported by the results.
• Uncertainties : Account for uncertainties and errors. Explain, for example, if there were other circumstances beyond your control that might have impacted the experiment’s results.
• New : Discuss new questions or discoveries that emerged from the experiment.

• Your assignment may also have specific questions that need to be answered. Make sure you answer these fully and coherently in your conclusion.

Discussing the Experiment and Hypothesis

• If you tried the experiment more than once, describe the reasons for doing so. Discuss changes that you made in your procedures.
• Brainstorm ways to explain your results in more depth. Go back through your lab notes, paying particular attention to the results you observed. [3] X Trustworthy Source University of North Carolina Writing Center UNC's on-campus and online instructional service that provides assistance to students, faculty, and others during the writing process Go to source

• Start this section with wording such as, “The results showed that…”
• You don’t need to give the raw data here. Just summarize the main points, calculate averages, or give a range of data to give an overall picture to the reader.
• Make sure to explain whether or not any statistical analyses were significant, and to what degree, such as 1%, 5%, or 10%.

• Use simple language such as, “The results supported the hypothesis,” or “The results did not support the hypothesis.”

Demonstrating What You Have Learned

• If it’s not clear in your conclusion what you learned from the lab, start off by writing, “In this lab, I learned…” This will give the reader a heads up that you will be describing exactly what you learned.
• Add details about what you learned and how you learned it. Adding dimension to your learning outcomes will convince your reader that you did, in fact, learn from the lab. Give specifics about how you learned that molecules will act in a particular environment, for example.
• Describe how what you learned in the lab could be applied to a future experiment.

• On a new line, write the question in italics. On the next line, write the answer to the question in regular text.

• If your experiment did not achieve the objectives, explain or speculate why not.

Wrapping Up Your Conclusion

• If your experiment raised questions that your collected data can’t answer, discuss this here.

• Describe what is new or innovative about your research.
• This can often set you apart from your classmates, many of whom will just write up the barest of discussion and conclusion.

Community Q&A

• Ensure the language used is straightforward with specific details. Try not to drift off topic. Thanks Helpful 1 Not Helpful 0
• Once again, avoid using personal pronouns (I, myself, we, our group) in a lab report. The first-person point-of-view is often seen as subjective, whereas science is based on objectivity. Thanks Helpful 1 Not Helpful 0
• If you include figures or tables in your conclusion, be sure to include a brief caption or label so that the reader knows what the figures refer to. Also, discuss the figures briefly in the text of your report. Thanks Helpful 1 Not Helpful 0

• Take care with writing your lab report when working in a team setting. While the lab experiment may be a collaborative effort, your lab report is your own work. If you copy sections from someone else’s report, this will be considered plagiarism. Thanks Helpful 4 Not Helpful 0

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• ↑ https://phoenixcollege.libguides.com/LabReportWriting/introduction
• ↑ https://www.education.vic.gov.au/school/teachers/teachingresources/discipline/english/literacy/Pages/puttingittogether.aspx
• ↑ https://writingcenter.unc.edu/tips-and-tools/brainstorming/
• ↑ https://advice.writing.utoronto.ca/types-of-writing/lab-report/
• ↑ http://www.socialresearchmethods.net/kb/hypothes.php
• ↑ https://libguides.usc.edu/writingguide/conclusion
• ↑ https://libguides.usc.edu/writingguide/introduction/researchproblem
• ↑ http://writingcenter.unc.edu/handouts/scientific-reports/
• ↑ https://phoenixcollege.libguides.com/LabReportWriting/labreportstyle
• ↑ https://writingcenter.unc.edu/tips-and-tools/editing-and-proofreading/

About This Article

To write a good lab conclusion in science, start with restating the lab experiment by describing the assignment. Next, explain what you were trying to discover or figure out by doing the experiment. Then, list your results and explain how they confirmed or did not confirm your hypothesis. Additionally, include any uncertainties, such as circumstances beyond your control that may have impacted the results. Finally, discuss any new questions or discoveries that emerged from the experiment. For more advice, including how to wrap up your lab report with a final statement, keep reading. Did this summary help you? Yes No

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How to Write a Lab Report – with Example/Template

April 11, 2024

Perhaps you’re in the midst of your challenging AP chemistry class in high school, or perhaps college you’re enrolled in biology , chemistry , or physics at university. At some point, you will likely be asked to write a lab report. Sometimes, your teacher or professor will give you specific instructions for how to format and write your lab report, and if so, use that. In case you’re left to your own devices, here are some guidelines you might find useful. Continue reading for the main elements of a lab report, followed by a detailed description of the more writing-heavy parts (with a lab report example/lab report template). Lastly, we’ve included an outline that can help get you started.

What is a lab report?

A lab report is an overview of your experiment. Essentially, it explains what you did in the experiment and how it went. Most lab reports end up being 5-10 pages long (graphs or other images included), though the length depends on the experiment. Here are some brief explanations of the essential parts of a lab report:

Title : The title says, in the most straightforward way possible, what you did in the experiment. Often, the title looks something like, “Effects of ____ on _____.” Sometimes, a lab report also requires a title page, which includes your name (and the names of any lab partners), your instructor’s name, and the date of the experiment.

Abstract : This is a short description of key findings of the experiment so that a potential reader could get an idea of the experiment before even beginning.

Introduction : This is comprised of one or several paragraphs summarizing the purpose of the lab. The introduction usually includes the hypothesis, as well as some background information.

Lab Report Example (Continued)

Materials : Perhaps the simplest part of your lab report, this is where you list everything needed for the completion of your experiment.

Methods : This is where you describe your experimental procedure. The section provides necessary information for someone who would want to replicate your study. In paragraph form, write out your methods in chronological order, though avoid excessive detail.

Data : Here, you should document what happened in the experiment, step-by-step. This section often includes graphs and tables with data, as well as descriptions of patterns and trends. You do not need to interpret all of the data in this section, but you can describe trends or patterns, and state which findings are interesting and/or significant.

Discussion of results : This is the overview of your findings from the experiment, with an explanation of how they pertain to your hypothesis, as well as any anomalies or errors.

Conclusion : Your conclusion will sum up the results of your experiment, as well as their significance. Sometimes, conclusions also suggest future studies.

Sources : Often in APA style , you should list all texts that helped you with your experiment. Make sure to include course readings, outside sources, and other experiments that you may have used to design your own.

How to write the abstract

The abstract is the experiment stated “in a nutshell”: the procedure, results, and a few key words. The purpose of the academic abstract is to help a potential reader get an idea of the experiment so they can decide whether to read the full paper. So, make sure your abstract is as clear and direct as possible, and under 200 words (though word count varies).

When writing an abstract for a scientific lab report, we recommend covering the following points:

• Background : Why was this experiment conducted?
• Objectives : What problem is being addressed by this experiment?
• Methods : How was the study designed and conducted?
• Results : What results were found and what do they mean?
• Conclusion : Were the results expected? Is this problem better understood now than before? If so, how?

How to write the introduction

The introduction is another summary, of sorts, so it could be easy to confuse the introduction with the abstract. While the abstract tends to be around 200 words summarizing the entire study, the introduction can be longer if necessary, covering background information on the study, what you aim to accomplish, and your hypothesis. Unlike the abstract (or the conclusion), the introduction does not need to state the results of the experiment.

Here is a possible order with which you can organize your lab report introduction:

• Intro of the intro : Plainly state what your study is doing.
• Background : Provide a brief overview of the topic being studied. This could include key terms and definitions. This should not be an extensive literature review, but rather, a window into the most relevant topics a reader would need to understand in order to understand your research.
• Importance : Now, what are the gaps in existing research? Given the background you just provided, what questions do you still have that led you to conduct this experiment? Are you clarifying conflicting results? Are you undertaking a new area of research altogether?
• Prediction: The plants placed by the window will grow faster than plants placed in the dark corner.
• Hypothesis: Basil plants placed in direct sunlight for 2 hours per day grow at a higher rate than basil plants placed in direct sunlight for 30 minutes per day.
• How you test your hypothesis : This is an opportunity to briefly state how you go about your experiment, but this is not the time to get into specific details about your methods (save this for your results section). Keep this part down to one sentence, and voila! You have your introduction.

How to write a discussion section

Here, we’re skipping ahead to the next writing-heavy section, which will directly follow the numeric data of your experiment. The discussion includes any calculations and interpretations based on this data. In other words, it says, “Now that we have the data, why should we care?”  This section asks, how does this data sit in relation to the hypothesis? Does it prove your hypothesis or disprove it? The discussion is also a good place to mention any mistakes that were made during the experiment, and ways you would improve the experiment if you were to repeat it. Like the other written sections, it should be as concise as possible.

Here is a list of points to cover in your lab report discussion:

• Weaker statement: These findings prove that basil plants grow more quickly in the sunlight.
• Stronger statement: These findings support the hypothesis that basil plants placed in direct sunlight grow at a higher rate than basil plants given less direct sunlight.
• Factors influencing results : This is also an opportunity to mention any anomalies, errors, or inconsistencies in your data. Perhaps when you tested the first round of basil plants, the days were sunnier than the others. Perhaps one of the basil pots broke mid-experiment so it needed to be replanted, which affected your results. If you were to repeat the study, how would you change it so that the results were more consistent?
• Implications : How do your results contribute to existing research? Here, refer back to the gaps in research that you mentioned in your introduction. Do these results fill these gaps as you hoped?
• Questions for future research : Based on this, how might your results contribute to future research? What are the next steps, or the next experiments on this topic? Make sure this does not become too broad—keep it to the scope of this project.

How to write a lab report conclusion

This is your opportunity to briefly remind the reader of your findings and finish strong. Your conclusion should be especially concise (avoid going into detail on findings or introducing new information).

Here are elements to include as you write your conclusion, in about 1-2 sentences each:

• Restate your goals : What was the main question of your experiment? Refer back to your introduction—similar language is okay.
• Restate your methods : In a sentence or so, how did you go about your experiment?
• Key findings : Briefly summarize your main results, but avoid going into detail.
• Limitations : What about your experiment was less-than-ideal, and how could you improve upon the experiment in future studies?
• Significance and future research : Why is your research important? What are the logical next-steps for studying this topic?

Template for beginning your lab report

Here is a compiled outline from the bullet points in these sections above, with some examples based on the (overly-simplistic) basil growth experiment. Hopefully this will be useful as you begin your lab report.

1) Title (ex: Effects of Sunlight on Basil Plant Growth )

2) Abstract (approx. 200 words)

• Background ( This experiment looks at… )
• Objectives ( It aims to contribute to research on…)
• Methods ( It does so through a process of…. )
• Results (Findings supported the hypothesis that… )
• Conclusion (These results contribute to a wider understanding about…)

3) Introduction (approx. 1-2 paragraphs)

• Intro ( This experiment looks at… )
• Background ( Past studies on basil plant growth and sunlight have found…)
• Importance ( This experiment will contribute to these past studies by…)
• Hypothesis ( Basil plants placed in direct sunlight for 2 hours per day grow at a higher rate than basil plants placed in direct sunlight for 30 minutes per day.)
• How you will test your hypothesis ( This hypothesis will be tested by a process of…)

4) Materials (list form) (ex: pots, soil, seeds, tables/stands, water, light source )

5) Methods (approx. 1-2 paragraphs) (ex: 10 basil plants were measured throughout a span of…)

6) Data (brief description and figures) (ex: These charts demonstrate a pattern that the basil plants placed in direct sunlight…)

7) Discussion (approx. 2-3 paragraphs)

• Support or reject hypothesis ( These findings support the hypothesis that basil plants placed in direct sunlight grow at a higher rate than basil plants given less direct sunlight.)
• Factors that influenced your results ( Outside factors that could have altered the results include…)
• Implications ( These results contribute to current research on basil plant growth and sunlight because…)
• Questions for further research ( Next steps for this research could include…)
• Restate your goals ( In summary, the goal of this experiment was to measure…)
• Restate your methods ( This hypothesis was tested by…)
• Key findings ( The findings supported the hypothesis because…)
• Limitations ( Although, certain elements were overlooked, including…)
• Significance and future research ( This experiment presents possibilities of future research contributions, such as…)
• Sources (approx. 1 page, usually in APA style)

Final thoughts – Lab Report Example

Hopefully, these descriptions have helped as you write your next lab report. Remember that different instructors may have different preferences for structure and format, so make sure to double-check when you receive your assignment. All in all, make sure to keep your scientific lab report concise, focused, honest, and organized. Good luck!

For more reading on coursework success, check out the following articles:

• How to Write the AP Lang Argument Essay (With Example)
• How to Write the AP Lang Rhetorical Analysis Essay (With Example)
• 49 Most Interesting Biology Research Topics
• 50 Best Environmental Science Research Topics
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How to Write a Good Conclusion For a Lab Report

Writing a good conclusion for your science lab report can be the difference between a good grade and a great one. It's your last chance to show you understand the experiment and why it matters. This article will help you learn how to write a lab conclusion that sums up your work and shows your teacher that you understood what you did.

What Should Be in Your Lab Report Conclusion?

A good lab report conclusion wraps up your lab work in a neat package. When you're thinking about how to write a conclusion for a lab report, focus on four main things. First, remind everyone in a sentence or two of your experiment objectives. Then, quickly mention how you did the experiment and what you found out, but don't introduce new ideas.

Next, talk about the most important things you learned from your experiment. Show how what you found out connects to what you initially tried to do. Lastly, think briefly about what your work means or any limitations you faced during the process. You may include suggestions for further investigation but refrain from proposing solutions.

How to Write a Lab Report Conclusion

To write a good lab conclusion, follow these steps:

• Remind the reader why you did the experiment and its aims. 
• Describe how you did the experiment and what tools you used.
• Briefly discuss the samples used and the results obtained.
• Provide a short analysis, including your arguments and assumptions.
• Relate your findings to the broader scientific context of your discipline.

Important: Keep your conclusion short and easy to understand. A lab conclusion should be about 200-300 words or one paragraph. But if your experiment was really complex, you might need up to 500 words.

Remember, your lab conclusion is part of a bigger report. Always make sure your whole report is well-organized, with a title, introduction, how you did things, what you found, what it means, conclusion, and a list of where you got your information. If you have a lot of numbers or calculations, put them at the end in a separate section to make your report easier to read.

A Sample Lab Report Conclusion

Here's an example of how to write a scientific conclusion for a plant experiment:

The experiment examined how various light wavelengths impact tomato seedling growth. Our findings revealed that blue light (450-495 nm) significantly enhanced stem elongation and leaf surface area in tomato seedlings compared to red (620-750 nm) or full-spectrum white light. Throughout the 4-week study, seedlings exposed to blue light achieved an average height of 15.3 cm, surpassing those exposed to red (10.7 cm) and white light (12.1 cm).  These results align with our hypothesis that blue light promotes more vigorous vegetative growth in tomato seedlings, potentially due to its activation of phototropins and cryptochromes. While these outcomes provide valuable insights into early-stage tomato plant development, additional research is necessary to determine the long-term effects on fruit production and quality. This study contributes to our understanding of optimizing light conditions for improved seedling growth in controlled agricultural environments.

This example shows the important parts of a good lab conclusion: it reminds us what the experiment was for, tells how it was done, shares the results, and explains what it all means.

Useful Tips for Improving Your Lab Conclusion

To make your conclusion lab report better, try these tips:

• Review your grading rubric to ensure you meet all requirements.
• Maintain an appropriate tone (explanatory, descriptive, or process-oriented).
• Keep your notes nearby so you can check your facts.
• Use your own words to say what you were trying to do; don't just copy from your lab instructions.
• Use passive voice and past tense , typically avoiding first-person perspective. Most lab reports are written in the third person.

When writing a discussion lab report, focus on clarity and sticking to what's important. Don't add new information or discuss things that aren't part of your experiment.

Making Your Scientific Conclusion Clear and Impactful

Writing a great lab report conclusion doesn't have to be hard. With the tips we've discussed on writing a scientific conclusion, you can now write good summaries of your science work. Remember, when writing your discussion lab report, stay focused on your experiment and what you found out. Don't talk about things that aren't related or say things you can't prove. Instead, explain your results, their meaning, and why they matter in science.

Need a little extra help polishing your scientific writing? Aithor might be just what you're looking for. This nifty AI writing tool will streamline your essay and report writing processes. It keeps your original ideas intact while giving your work a professional shine. Whether tackling a tricky lab report or a complex essay, this tool can help you craft well-structured, engaging content in no time. 

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How to Write a Conclusion for a Lab Report

A conclusion in a lab report is a recap of the entire experiment or the study. Starting from the purpose of the experiment to its result and subsequent interpretations of the result, a lab report conclusion effectively summarizes all the steps of the experiment. 

Structure of a Lab Report Conclusion

Similar to the lab report abstract , which appears at the beginning of the lab report , the conclusion provides the reader with an overview of the experiment. While both have a similar structure, there is an important difference between an abstract and a conclusion. While an abstract summarizes the key points of the experiment, a conclusion is more elaborate and sheds light on the result of the experiment. A lab report conclusion: 

• Restates the objective of the experiment: A good way to begin a conclusion paragraph is to restate the purpose of or the objective of the experiment mentioned in the introduction part of the lab report . This should also include the main hypothesis . 
• Discusses the key findings: It is a common practice to include a separate discussion paragraph that lays down the outcome of the experiment in detail. However, in some cases, the lab report conclusion paragraph also contains the discussion part, which provides additional information on the outcome of the experiment. 
• Revisits the hypothesis: The outcome of an experiment either proves, disproves, or partially proves the hypothesis. The conclusion revisits the hypothesis and notes whether or not the evidence (obtained during the course of the experiment) supports or refutes the hypothesis. 
• Clarifies assumptions made and notes limitations: In some cases, while conducting an experiment, certain assumptions are made due to the limitations of a study. For instance, while conducting a Physics lab experiment, if the actual mass of the objects used in the experiment is different from the intended mass, then depending on the variation, the result of the experiment may be different from the hypothesis made. It is, however, assumed at the time of the experiment that the actual mass of the objects is the same as the intended mass. This assumption is made due to a limitation, which in this case is the unavailability of objects with the required mass. The conclusion is incomplete if it doesn’t note such assumptions and limitations.
• Records corrections: If the obtained result of an experiment is drastically different from the intended result, then certain adjustments are made to obtain the desired result. For the conclusion to be accurate, it’s important that it mentions corrections or adjustments made while conducting the experiment. 
• Provides recommendation: A good lab report conclusion is one which provides recommendation of what the next steps should be after the experiment has been completed. The recommendation could be a reference to a similar study or scientific journals and articles that provide additional information or any improvements that can be made to better the result of the experiment. 

Lab Report Conclusion Example 

Below is the conclusion of a lactase enzyme specificity experiment, which clearly states all the key information related to the outcome. 

For our lactase enzyme specificity experiment, we concluded our hypothesis that enzymes are specific and will only break down lactose, but not sucrose. This was proven with the data we collected. We found that only the test tube containing milk and lactase was able to have an enzymatic reaction releasing 1000 mg/dL of glucose. This gave proof to our prediction that if lactase is specific, it may only break down lactose. Enzyme lactase is specificity-hydrolyzed lactose.

Using the RERUN Method to Write a Conclusion

One of the most commonly used methods when it comes to writing a lab report conclusion is the ‘RERUN’ method. This method recapitulates all the key steps of an experiment:

R estate: Recapping the entire experiment, including the hypothesis and what was expected of the experiment, is a good way to conclude the report. 

E xplain: This step elaborates on the purpose of the experiment, the methods used, and any other important part of the experiment. 

R esult: After elaborating on the purpose of the experiment, the next step is to explain the result of the experiment and its interpretation. 

U ncertainties: Any uncertainties that can affect the result, such as assumptions made or limitations to the experiment, should be noted in the conclusion section. 

N ew: Anything new that is learned during the experiment should also be included in the conclusion of the lab report. 

Tips for Writing a Lab Report Conclusion

A lab report conclusion should be comprehensive and precise. Also, it should:

• Clearly state any possible errors that may have occurred during the course of the experiment. 
• Follow the rules of formal writing . 
• Specifically answer the research question the experiment is based on. 
• Provide proper references and citations . 
• Avoid repetitions. Stating something more than once only adds to the length of the conclusion paragraph. 
• Follow the guidelines outlined by the instructor or the college. 
• Use a grammar checker to perform thorough grammar checks.

From the main takeaways to making sense of the key findings of the study, a conclusion explicates some important aspects of the experiment and is therefore a crucial element of the lab report.  

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Lab reports are an essential part of all laboratory courses and usually a significant part of your grade. If your instructor gives you an outline for how to write a lab report, use that. Some instructors require a lab report to be included in a lab notebook , while others will request a separate report. Here's how to write a lab report you can use if you aren't sure what to write or need an explanation of what to include in the different parts of the report.

A lab report is how you explain what you did in ​your experiment, what you learned, and what the results meant.

Lab Report Essentials

Not all lab reports have title pages, but if your instructor wants one, it would be a single page that states:​

• The title of the experiment.
• Your name and the names of any lab partners.
• Your instructor's name.
• The date the experiment was performed or the date the report was submitted.

The title says what you did. It should be brief (aim for ten words or less) and describe the main point of the experiment or investigation. An example of a title would be: "Effects of Ultraviolet Light on Borax Crystal Growth Rate". If you can, begin your title using a keyword rather than an article like "The" or "A".

Introduction or Purpose

Usually, the introduction is one paragraph that explains the objectives or purpose of the lab. In one sentence, state the hypothesis. Sometimes an introduction may contain background information, briefly summarize how the experiment was performed, state the findings of the experiment, and list the conclusions of the investigation. Even if you don't write a whole introduction, you need to state the purpose of the experiment, or why you did it. This would be where you state your hypothesis .

List everything needed to complete your experiment.

Describe the steps you completed during your investigation. This is your procedure. Be sufficiently detailed so that anyone can read this section and duplicate your experiment. Write it as if you were giving directions for someone else to do the lab. It may be helpful to provide a figure to diagram your experimental setup.

Numerical data obtained from your procedure usually presented as a table. Data encompasses what you recorded when you conducted the experiment. It's just the facts, not any interpretation of what they mean.

Describe in words what the data means. Sometimes the Results section is combined with the Discussion.

Discussion or Analysis

The Data section contains numbers; the Analysis section contains any calculations you made based on those numbers. This is where you interpret the data and determine whether or not a hypothesis was accepted. This is also where you would discuss any mistakes you might have made while conducting the investigation. You may wish to describe ways the study might have been improved.

Conclusions

Most of the time the conclusion is a single paragraph that sums up what happened in the experiment, whether your hypothesis was accepted or rejected, and what this means.

Figures and Graphs

Graphs and figures must both be labeled with a descriptive title. Label the axes on a graph, being sure to include units of measurement. The independent variable is on the X-axis, and the dependent variable (the one you are measuring) is on the Y-axis. Be sure to refer to figures and graphs in the text of your report: the first figure is Figure 1, the second figure is Figure 2, etc.

If your research was based on someone else's work or if you cited facts that require documentation, then you should list these references.

• The Most Dangerous Elements on the Periodic Table
• Is It Safe to Reboil Water?
• What Are the Most Deadly Poisons and Chemicals?
• How to Balance Chemical Equations
• How to Draw a Lewis Structure
• Chemistry Glassware Types, Names and Uses
• Back Titration Definition
• Molarity Definition in Chemistry
• Understanding Endothermic and Exothermic Reactions
• Actual Yield Definition (Chemistry)
• How to Balance Equations - Printable Worksheets
• Chemical Properties of Matter
• General Chemistry Topics
• Examples of 10 Balanced Chemical Equations
• Ionic Compound Properties, Explained
• Ionic vs. Covalent Bonds: How Are They Different?

Princeton Correspondents on Undergraduate Research

How to Write An Effective Lab Report

Whether you are in lab for general chemistry, independent work, or senior thesis, almost all lab experiments will be followed up with a lab report or paper. Although it should be relatively easy to write about an experiment you completed, this is often the most difficult part of lab work, especially when the results are unexpected. In this post, I will outline the components of a lab report while offering tips on how to write one.

Understand Your Experiments Thoroughly

Before you begin writing your draft, it is important that you understand your experiment, as this will help you decide what to include in your paper. When I wrote my first organic chemistry lab report, I rushed to begin answering the discussion questions only to realize halfway through that I had a major conceptual error. Because of this, I had to revise most of what I had written so far, which cost me a lot of time. Know what the purpose of the lab is, formulate the hypothesis, and begin to think about the results you are expecting. At this point, it is helpful to check in with your Lab TA, mentor, or principal investigator (PI) to ensure that you thoroughly understand your project. 

The abstract of your lab report will generally consist of a short summary of your entire report, typically in the same order as your report. Although this is the first section of your lab report, this should be the last section you write. Rather than trying to follow your entire report based on your abstract, it is easier if you write your report first before trying to summarize it.

Introduction and Background

The introduction and background of your report should establish the purpose of your experiment (what principles you are examining), your hypothesis (what you expect to see and why), and relevant findings from others in the field. You have likely done extensive reading about the project from textbooks, lecture notes, or scholarly articles. But as you write, only include background information that is relevant to your specific experiments. For instance, over the summer when I was still learning about metabolic engineering and its role in yeast cells, I read several articles detailing this process. However, a lot of this information was a very broad introduction to the field and not directly related to my project, so I decided not to include most of it. 

This section of the lab report should not contain a step-by-step procedure of your experiments, but rather enough details should be included so that someone else can understand and replicate what you did. From this section, the reader should understand how you tested your hypothesis and why you chose that method. Explain the different parts of your project, the variables being tested, and controls in your experiments. This section will validate the data presented by confirming that variables are being tested in a proper way.

You cannot change the data you collect from your experiments; thus the results section will be written for you. Your job is to present these results in appropriate tables and charts. Depending on the length of your project, you may have months of data from experiments or just a three-hour lab period worth of results. For example, for in-class lab reports, there is usually only one major experiment, so I include most of the data I collect in my lab report. But for longer projects such as summer internships, there are various preliminary experiments throughout, so I select the data to include. Although you cannot change the data, you must choose what is relevant to include in your report. Determine what is included in your report based on the goals and purpose of your project.

Discussion and Conclusion

In this section, you should analyze your results and relate your data back to your hypothesis. You should mention whether the results you obtained matched what was expected and the conclusions that can be drawn from this. For this section, you should talk about your data and conclusions with your lab mentors or TAs before you begin writing. As I mentioned above, by consulting with your mentors, you will avoid making large conceptual error that may take a long time to address.

There is no correct order for how to write a report, but it is generally easier to write some sections before others. For instance, because your results cannot be changed, it is easier to write the results section first. Likewise, because you also cannot change the methods you used in your experiment, it is helpful to write this section after writing your results. Although there are multiple ways to write and format a lab report or research paper, the goals of every report are the same: to describe what you did, your results, and why they are significant. As you write, keep your audience and these goals in mind.

— Saira Reyes, Engineering Correspondent

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Chemistry Lab Resources (for CHM 1XX and 2XX Labs)

• Organizing Your Lab Notebook
• Parts of a Lab Report
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• Chemical Safety

General tips

Whether you are filling out lab worksheets or writing up entire lab reports, there are a few tips that will help you to create more detailed and professional documents and to assist in grading:

• Always label your units
• Show all of your calculations (don’t leave out steps)
• Use complete sentences
• Write neatly
• Strike out mistakes with a single line
• Be aware of significant figures, noting the sensitivity of the device you are using for your measurements

Why do we write lab reports in passive voice?

It’s part of the scientific point of view.  We observe and record as objectively as possible, avoiding personal bias by removing ourselves.  Using the passive voice also clarifies procedures and descriptions so they can be easily reproduced and compared.

NOTE: DO NOT write reports as directions, such as those given in your lab manual. For example, do not write, "Heat the solution until it boils." Instead, write "The solution was heated to boiling."

Write in the third person - Scientific experiments demonstrate facts that do not depend on the observer, therefore, reports should avoid using the first and second person (I,me,my,we,our, OR us.)

Using the correct verb tense - Lab reports and research papers should be mainly written in the present tense. You should limit the use of the past tense to (1) describe specific experimental methods and observations, and (2) citing results published in the past.

Tables and Figures - Should be used when they are a more efficient ways to convey information than verbal description. They must be independent units, accompanied by explanatory captions that allow them to be understood by someone who has not read the text.

Writing in the passive voice

Examples of passive voice in lab reports.

200mL of distilled water was poured into a 500 mL beaker.

I poured 200mL of distilled water in a beaker. (active voice)

Pour 200mL water in a beaker. (direction/command)

The covered crucible was mounted on a ring stand.

We put the crucible on a ring stand. (active voice)

Set the crucible on a ring stand. (direction/command)

The temperature was initially measured at 75°C.

I measured the temperature at 75°C. (active voice)

Measure and write down the temperature. (direction/command)

It's understood that all actions were done by the experimenter.

Avoiding Plagiarism

• Avoiding Plagiarism From Purdue's OWL

Passive voice information derived from original work at Delta College Teaching/Learning Center

http://www.delta.edu/files/TLC/Writing%20Lab%20Reports%2009.doc

Writing a Lab Report

Purdue students explain strategies for dividing the workload for writing a lab report.

Sample Lab Reports

• Determination of the Alcohol Content of Whiskey [Courtesy of Univ. of Oregon]
• Synthesis and Characterization of Luminol [Courtesy of Truman State Univ.]
• Production of Biodiesel [Courtesy of Univ. of Vermont]
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• Phoenix College

Lab Report Writing

• Discussion/Conclusion
• Lab Report Style
• Lab Report Format
• Introduction
• Materials and Methods

Discussion or Conclusion

Test yourself (discussion).

Once you've discussed the most important findings of your study in the Results section, you will use the Discussion section to interpret those findings and talk about why they are important (some instructors call this the Conclusion section). You might want to talk about how your results agree, or disagree, with the results from similar studies. Here you can also mention areas ways you could have improved your study or further research to be done on the topic. Do not just restate your results - talk about why they are significant and important. Here's a paragraph taken from the Discussion from the bone fracture paper. Notice how the authors relate their results to what is already known about the topic. The numbers in brackets refer to references listed at the end of their paper (not shown here).

The data indicate that avoiding a low level of physical activity substantially reduces the risk of all fractures, particularly hip fractures—the most devastating of osteoporotic fractures—in men. Even changes in physical activity during the follow-up affected hip fracture risk. As expected, those who maintained a high physical activity level had the lowest risk of hip fracture, but there was also a tendency towards a lower risk of fracture for those who increased their level of activity compared with those who reduced their level of activity, or compared with those who reported constant low activity. This observation has previously been made in women [8,16]. There are several possible mechanisms, related to muscle performance and balance as well as to bone architecture and strength, whereby physical activity can reduce the risk of fractures [28,29].

Which of the following is a good example of a sentence you would find in the Discussion section of a lab report?

a. Ten dogs with no previous training were selected for the study. b. Unlike in previous studies on dog training, most of the dogs in this study retained the ability to perform tricks for up to six weeks after the initial training sessions. c. Seven of the ten dogs learned how to "sit" after three training sessions. d. It was hypothesized that the dogs would be able to retain all of the training commands for six weeks after the initial training sessions.

B The Discussion should interpret the findings from the study and relate them to other similar studies. It is not the place to talk about the results, the methods use, or the original hypothesis.

Click on the question, to see the answer.

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How to Write a Conclusion for a College Lab Report

Writing lab reports is a crucial part of many college science courses. In a lab report, you detail your experiment from start to finish. This process involves outlining your procedures, recording your results and analyzing your data. 

The conclusion paragraph is one of the most important elements of your lab report. It is your opportunity to summarize your experiment and identify your main takeaways. A strong conclusion conveys your experiment's objectives and how they connect to your findings.

What to Include in a Lab Report Conclusion

You can follow a few steps to craft an effective lab report conclusion:

1. Restate the Experiment's Goals

Start your conclusion paragraph with one or two sentences outlining the purpose of your experiment. 

2. Describe the Methods Used

Briefly summarize the process you went through to complete the experiment.

3. Include and Analyze the Final Data

Describe your results and explain what they mean in the context of your experiment.

4. State Whether Your Experiment Succeeded

Explain whether your data supported your hypothesis. You should also outline any takeaways for future experiments, such as changes you would make and how you could expand the experiment.

Example of an Effective College-Level Lab Report Conclusion

Generally speaking, your lab report conclusion should be a well-developed paragraph that addresses the above points. Keep in mind that the specific length of your conclusion will vary depending on the complexity of your report.

You can use the below example as a reference while you craft your conclusion:

The goal of this experiment was to investigate the effect of stress on tomato plant growth. It compares the growth of tomato plants subjected to stress for 14 days to a control group of tomato plants not subjected to stress. The stressed tomato plants were exposed to high temperatures and received insufficient amounts of water. As the graph shows, the average height of the stressed tomato plants was 2.5 feet, and the average height of the nonstressed tomato plants was 3 feet. The height difference supports the hypothesis that stress stunts tomato plant growth. Additional experiments could study the effects of stress over a longer period. Subjecting other crops like squash or corn to the same experiment could also provide valuable information.

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How to write a lab report conclusion.

Like other reports, without a conclusion, a lab report is incomplete. Conclusions are an integral part of lab reports and are fundamental to the demonstration of report objectives and reiteration of findings.

Although conclusions are often short, confined to a paragraph, they are nonetheless some of the most difficult aspects of a lab report.

This article will, therefore, explain how to write a good conclusion for a lab report. But before that, it will remind you of the basics and format of lab reports for a comprehensive exposition.

Basic Lab Report

All reports describe the process of an experiment or a study from the beginning to the end. There are several categories of reports and a lab report is one of them.

A lab report follows the same routine as a typical report. Except that in a lab report, you are mostly dealing with scientific and laboratory experiments. In other words, a lab report describes the process of a scientific and laboratory experiment from the beginning to the end.

A lab report is required to test what students — whether chemistry students or biology students — had learned in the course of an experiment.

Ideally, a lab report begins with an introduction and ends with a conclusion. Conclusion is often the part where the results of experiments are reiterated and readers are provided with a short but general overview of the whole process.

Science Lab Report Format

Unlike other reports, a lab report is fundamentally a science experiment report. A scientific report documents the process, procedures, and findings of scientific research.

An example of a scientific report is an academic essay a teacher asked you to submit about technology or the one you wrote about cancer.

Whether your lab report is biological or chemical, there is a format to all scientific reports. A typical scientific laboratory report will contain:

• Purpose: A brief description of what the research is all about, including the methods used and the resources available to the student.
• Hypothesis: Guess statements on expected results of the scientific experiment.
• Procedure: A step-by-step guide and instructions followed by the student in the course of the experiment.
• Lab Safety: Safety precautions adhered to by the student throughout the experiment.
• Data: Recorded experimental data generated on the experiment by the student.
• Observations: The sudden burst of insight and perspectives about the experiment.
• Results: The findings of the student from the experiment through collected data and observations.
• Conclusion: Summary of the experiment, most especially as the findings relate to the report’s purpose and hypothesis.

Lab Report Conclusion

As a university or college science student, writing a lab report might not be new to you but it is a challenging process. This is because the whole lab report structure consumes. From the objective of the experiment to lab report conclusions, each structure wrestles for time.

Learning how to write a discussion and conclusion for a lab report is not the same as learning how to write a lab report itself. While it could be said that knowing the latter should help with the former, it is not always so. There are several examples of great lab reports with shabby conclusions.

Conclusions can prove tricky and this is the reason why you need to learn how to write them. To conclude lab reports, you would need to be familiar with the lab report conclusion outline (also called the lab report conclusion template). You can consider the following 5 outlines:

The first step to take before you conclude your reports is to assess the whole report from the beginning to where it stopped. This means you would need to visit and revisit the whole experiment to be sure that no structure of your report is left out.

The purpose of this is for you to go through the process of the report again. Experiments are usually consuming and at some points, you might get lost or stuck in a part and thereby lose that sense of touch with other parts. But if you can assess the whole experiment again, it would be easy to jot down the process in the report for a succinct conclusion.

After you might have assessed the whole report, you would need to pay more attention to the introduction of your report under this step. You should be looking at the proposed purpose of your report here and see if it tallies with what you intend to conclude with.

The introductory part of your report must align with the conclusive part. The introduction part should not be saying something different from the conclusion unless your report risks a crime of inconsistency. Consistency is essential to every great scientific and laboratory report.

Now that you have assessed the general report and the introductory, the next stage is to apply the RERUN Method to conclude your report. The RERUN is a useful acronym for integrating the essential parts of your experiment in your conclusion. Just as the rest of the report, conclusions also contain key ingredients.

RERUN stands for Restate, Explain, Results, Uncertainties , and New . To brilliantly conclude your report, you would need to follow the acronym and apply what each letter stands for.

When you want to conclude, you should Restate the lab experiment and Explain what the whole project is set out to achieve. Then proceed to explain the Results through the generated data and confirmation of the hypothesis. After that, make provisions for the Uncertainty and discuss New matters or solutions arising from the experiment.

• Add Sections If necessary, you should add other sections of your experiment. Depending on the purpose of your project, you might need to add your data procedures or part of your observations to it. While the RERUN Method is a great way to conclude, it is not absolute. For instance, you may ask yourself “What is the importance of calculations in a lab report or my lab report?” and try to include the section where necessary.
• Conclusive Assessment Once you are done with the conclusion, you should assess that part again. You should look out for errors, consistency, and how the whole part of your report reads with and without that portion of the added conclusion. How long should a lab report conclusion be? It should be as concise and precise as possible.

Examples of Lab Report Conclusion

Provided are examples of a good scientific report conclusion and a bad one. The good one follows the outlines of concluding a report while the bad one negates the outlines. Through the examples, you can glean how best to conclude your report.

Good Example

A good report conclusion will contain all 5 outlines (mentioned above) that can be deployed for summing up your reports. Here is an example:

“In conclusion, team management is a process and only indicates the many strategies that go into it, helped by effective decision-making sequential and procedural. Since most decisions begin from problems, it is pertinent that the processes of decision-making reflect the identification of problems, definition of them, decision, action, and feedback. Through the sequences, it would be noted that decision-making can be programmed or non-programmed, depending on the flexibility and occurrence; and can be operational, tactical, or strategic, depending on the duration of the problem needed to be solved. Besides, there are styles of decision-making, informed by actions. These actions, however, should always be checked and balanced through effective feedback.”

Before the report conclusion was written, a general assessment of the whole report was made to jot down the process and relearned the experience. The first report hinges on team management and decision-making, both themes were justified.

Also, through an introductory assessment, the topic sentence and purpose of the report were clear. The conclusion was well-organized and the report was not bereft of the conclusion outlines not excluding the RERUN Method.

Bad Example

This is one of the examples of a bad report conclusion.

“The infant stage is considered fundamental. It is the stage where all other stages are premised. It is thus plausible that development theories be looked at from this stage. The stage shows how Piaget’s and Vygotsky’s theories work, which in turn provide perspectives to understanding breastfeeding and mental health in infants.”

From the conclusion, it can be gleaned that the report does not follow the outlines as well as the RERUN Method. The thesis statement was unclear and the conclusion itself seems hurriedly done.

Need Help With Writing a Lab Report Conclusion?

Learning how to write a conclusion for a biology lab report or a chemistry lab report or just any other lab report can be challenging. You could bypass the challenges, anyway, by hiring cheap and trusted homework help or an expert. You would need to be certain they could be trusted with your deadline and are quality enough to earn you top grades in class. Otherwise, you should learn the nitty-gritty of lab reports yourself.

It shouldn’t be difficult to learn how to end a conclusion in a lab report, considering that this article has taken you through the process of lab report itself and then the outlines of lab report conclusions. Also provided are lab report conclusion examples — both good and bad — that you can model yours after.

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6.4: Hypothesis Testing

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Probability and Hypothesis Testing

Hypothesis testing is a process by which data are analyzed and conclusions are drawn about whether the results support or refute the hypothesis. This process allows statisticians to determine the likelihood that their results are not due to chance and, instead, likely represent truths about populations that are in keeping with their hypotheses. Note that the tenet of probability (introduced in Chapter 1) is a component of this process. When a hypothesis is tested, steps are followed and calculations are performed to assess the probability (likelihood) that a hypothesis is true based on sample data. Thus, the terms supported and refuted are used instead of the words proven and disproven, respectively.

Hypotheses come in a variety of forms, each of which requires different statistical methods of analysis. Some hypotheses, like the one about oatmeal and cholesterol from earlier in this chapter, state that a treatment condition (or intervention) will cause a difference in a measurable outcome variable. To review, that hypothesis written in sentence and symbol formats is:

Cholesterol levels will be lower after (post) eating oatmeal daily for six weeks compared to before (pre).

\(H_a: \mu_{\text {post }}<\mu_{\text {pre }}\)

In this example daily oatmeal consumption is the treatment condition and cholesterol level is the outcome being measured. We can see from the symbol format that data will need to be collected from a sample both before the treatment in order to compute a pretest mean and again from the same sample after the treatment in order to compute a posttest mean. The means can then be compared to see if, as is expected based on the hypothesis, the mean cholesterol level for the sample is lower at posttest than it was at pretest.

It is tempting and seems logical to simply conclude that if the posttest mean is even slightly lower than the pretest mean, the hypothesis is supported. However, before we can draw this conclusion we need to assure that our results are strong enough to conclude that the difference is unlikely to simply be due to chance and that they, instead, likely reflect a real difference in the means. This is because sample means are estimates and are expected to have some sampling error; sample means are not expected to be perfect representations of population parameters under the same conditions. Slight differences in means could simply be due to sampling error. Thus, estimates of error (such as the standard deviation or standard error) must also be considered in order to determine how likely it is that the difference in the pretest and posttest sample means represent an actual difference that would be observed in population parameters under the same conditions. For this reason, estimates of error are an important part of statistical power and determining significance.

Statistical Power and Significance

Statistical power refers to how likely it is that sample data will support the hypothesis. Think of statistical power as the ability to detect that an alternative hypothesis is true if, in fact, it is true. Power is generally increased or decreased by three factors:

• the size of the sample,
• the size of the change, difference, or pattern observed in the sample data, and
• the size of the error in the relevant estimates of the changes, differences, or patterns observed.

First, if the hypothesis is true, data to support it are more likely when the sample is larger than when it is smaller. Therefore, as sample sizes increase, power also increases. Second, if the change, difference, or pattern observed in the sample is larger or clearer, it is easier to detect and is more likely to represent a difference that would occur in the population than if it is smaller. Thus, as the size of changes, differences, or patterns observed increases, power also increases. Finally, the lower the error is, the closer the observations are expected to be to the parameters of a population. Thus, as the size of error decreases, power increases. Considering these three things together, we can summarize the components that increase power as follows:

• The larger the sample size, the more closely the sample statistics are expected to represent the population.
• The larger or clearer the change, difference, or pattern observed in the sample, the more likely it is that it reflects a change, difference, or pattern in the population.
• The less error there is in the sample statistics used to assess changes, differences, or patterns, the more likely it is that they reflect changes, differences, or patterns in the population.

Obtained Values

These components that impact statistical power are interconnected. Means are estimates for which variability must be considered. Some measures of variability and error (such as standard errors) include sample sizes in their calculations. Further, the greater the sample size, the closer a sample is to being equivalent to its population size. Thus, the formulas used in inferential statistics include variations of some or all of the three components of power to yield one of several forms of obtained values. Obtained values are results that summarize data by using inferential formulas. Inferential formulas are those used to test hypotheses. These formulas and other analyses that accompany them take into account the components of power. Data are plugged into inferential formulas which yield obtained values. Those obtained values are compared to specific thresholds to assess whether the data supported or failed to support a hypothesis. Thus, obtained values can be thought of as summaries of how much power or evidence there is to support a hypothesis.

Determining Significance

Statistical significance refers to the determination that a hypothesis is likely true in the population because there is sufficient evidence in the sample to support the hypothesis. Another way to say this is that a statistically significant result occurs when the hypothesized result was observed in the sample with enough power to conclude that the observed result was unlikely to be simply due to random chance. Essentially, when an obtained value is high enough for a given situation, it represents sufficient evidence to declare a hypothesis is significantly supported.

Significance is not absolute. Instead, it is a determination that a hypothesis is likely true but not that it is proven to be true. Recall that sampling error is assumed whenever a sample is drawn and used to represent a population. Recall also that there is no guarantee that the sample will represent the population well. Thus, there is always some chance that a hypothesis is not true in the population but that it will appear to be true in the data from a sample. The stronger the evidence is in favor of the hypothesis within the sample, the more likely it is that the hypothesis is true of the population. To say it another way, the stronger the results are, the less likely it is that they would have occurred simply due to random chance rather than because they are true. Therefore, when a result matches a hypothesis and is significant, statisticians conclude that a hypothesis is likely true and, thus, is supported by the evidence. Note that statistical significance is not necessarily indicative that a result is meaningful or useful. Instead, statistical significance simply indicates that the hypothesis is likely true based on the evidence.

Critical Values

Obtained values are compared to critical values to determine whether a hypothesis has enough evidence to be declared significant and, thus, supported. Critical values represent thresholds of the minimum amount of evidence that is needed to determine statistical significance and conclude that a hypothesis is supported. Thus, when the obtained value (which represents the amount of evidence) exceeds the critical value (which represents the minimum amount of evidence needed to support a hypothesis), the conclusion is that the hypothesis is supported. Conversely, when the obtained value does not exceed the critical value, the conclusion is that there is insufficient evidence to support the hypothesis. Another way to say this is that the null hypothesis is rejected when the obtained value exceeds the critical value and is retained or accepted when the obtained value does not exceed the critical value.

Obtained and critical values depend on several things which can include whether or not a hypothesis is directional, which inferential formula was used, and the relevant components of power for the hypothesis and corresponding formula used. We will review the specific differences and ways both obtained values and their critical values are found in subsequent chapters. For now, it is only necessary to know that each time a hypothesis is tested, an obtained value must be found, a critical value must be found, and the two must be compared. These are important steps in the larger processes of hypothesis testing.

Steps in Hypothesis Testing

In order to test a hypothesis, these steps should be followed, in the recommended order:

1. State the hypothesis.

This is a necessary first step. Before a study can be designed, a researcher needs to specify exactly what the hypothesis is what they intend to test. Then the process for collecting data (which is the research method) can be developed and carried out, accordingly.

It is worth noting that it is possible to develop a hypothesis after data have been collected but this is not ideal as it introduces important limitations to the research process. Though these limitations are beyond the scope of this book, they are an important topic which is generally covered in a Research Methods course. The focus of this book is best practices for statistical analysis; in keeping, we will always presume a hypothesis was developed before data were collected to test it. Thus, the first step for our analyses and reporting our results will always include stating the hypothesis.

2. Choose the inferential test (formula) that best fits the hypothesis.

There are a variety of formulas, each of which best fits only certain kinds of data and, thus, each only fits certain hypotheses. For example, one test is used to compare the means of the same group at posttest to itself at pretest, a different one is used to compare the mean of one group to the mean of a different group, another is used to compare the means of three or more distinct groups, and still others are used to assess patterns between two or more quantitative variables. The test selected should be the one that is best suited to the hypothesis under investigation. Note: A brief summary of the different kinds of inferential tests included in this book appears towards the end of this chapter.

3. Determine the critical value.

The critical value refers to the number you must surpass in order to conclude that your results are unlikely to be due to chance and, thus, likely reflects a truth about the population. The critical value is a concept we will discuss in more detail in subsequent chapters. For now, know that we weigh the implications of an inaccurate conclusion (e.g. what are the risks of concluding our medication worked when it actually did not) and then set the statistical risk we are willing to take that we might be wrong (which is used to determine the critical value). In the behavioral sciences, we very often decide that we are willing to accept less than a 5% chance that we will conclude a hypothesis is true when it is not; this means we want less than a 5% chance that our result is simply a false positive. Thus, critical values are usually computed to represent the amount (or strength) of evidence that is needed to be at least 95% confident that the hypothesis is true.

4. Calculate the test statistic.

This is the step of the scientific method (and, thus, also in the process of hypothesis testing) in which data are analyzed. In this step, the statistician uses the inferential test that was chosen in step 2 to analyze the data and yield a result. The result is represented by the obtained value (which is also known as a test statistic or result). This is the most math-intensive step of testing a hypothesis.

5. Apply a decision rule and determine whether the result is significant.

In this step, we assess whether our result (i.e. our obtained value or test statistic) exceeds the critical value. When it does, we can conclude that there is a strong probability that the hypothesis is true in the population based on the evidence observed in the sample. In so doing, the result is concluded to be significant. Conversely, when the test statistics does not exceed the critical value, we conclude that the evidence is not strong enough to conclude that the hypothesis is likely true in the population and, thus, that the hypothesis is not supported. In so doing, the result is concluded to be non-significant.

When a result is close to exceeding the critical value but does not, it may be prudent for researchers to retest the hypothesis or similar hypotheses with new samples in the future. A result which is close to, but does not surpass, the critical value may be referred to as “trending”; however, trending results should not be referred to as significant.

When it is determined that the result is significant, proceed through each of the remaining steps. When it is determined that the result is not significant, skip to step 7 to complete the process of hypothesis testing.

6. Calculate the effect size and other relevant secondary analyses.

An effect size can be reported alongside a significant result. Essentially, an effect size is an estimate of the magnitude of an effect, change, or pattern observed in the sample data. Effect size can help statisticians and audiences deduce practical significance. Practical significance refers to whether there is a large enough magnitude of effect to be meaningful or useful. This is important because it is possible to have a result that is statistically significant without being practically significant. Thus, it is often recommended that practical significance be reported as a secondary analysis when a result is statistically significant.

Some tests have additional secondary analyses which are necessary to adequately test a hypothesis. In each chapter for which these are recommended, they will be included in the section for step 6 of hypothesis testing.

7. Report the results in American Psychological Associate (APA) format.

Results for inferential tests are often best summarized using a paragraph that states the following:

• The hypothesis and specific inferential test used,
• The main results of the test and whether they were significant,
• Any additional results that clarify or add details about the results, and
• Whether the results support or refute the hypothesis.

It is recommended that effect sizes be reported with the additional results, when possible and/or common in the field into which the researcher is disseminating results. Dissemination refers to the formal sharing of results which is often done through publishing peer-reviewed, empirical articles in research or academic journals, giving conference presentations, and/ors reporting results in books that focus on summarizing several empirical studies. APA format specifies the level of rounding and types of symbols which should be used when reporting results for each of the various descriptive and inferential tests.

We will employ these steps when we learn how to select and properly use inferential statistics to test hypotheses in the subsequent chapters of this book. In each of those chapters, the details of the formulas, the calculations they require, and the symbols and rounding rules will be covered in detail. It will likely be helpful to refer back to this section with each of those chapters to remind yourself of the order and purpose of each of these steps to testing a hypothesis and reporting the results.

Reading Review 6.3

• In which step of hypothesis testing are data analyzed?
• What does statistical significance mean?
• Which two values are compared to determine whether a result is statistically significant?
• What is used to estimate practical significance?