Logic of the t test.
Read Assessment 3 Context [DOC] for important information on the following topics:
- Logic of the t test.
- Assumptions of the t test.
- Hypothesis testing for a t test.
- Effect size for a t test.
- Testing assumptions: The Shapiro-Wilk test and Levene’s test.
- Proper reporting of the independent-samples t test.
- t, degrees of freedom, and t value.
- Probability value.
- Effect size.
As you prepare to complete this assessment, you may want to think about other related issues to deepen your understanding or broaden your viewpoint. You are encouraged to consider the questions below and discuss them with a fellow learner, a work associate, an interested friend, or a member of your professional community. Note that these questions are for your own development and exploration and do not need to be completed or submitted as part of your assessment.
Various Forms of the t Test
- In what research situations should the paired-samples t test be used rather than the independent-samples t test?
Two Versions of the Independent-Samples t Test
- Why are there are two different versions of the t test on the SPSS printout and how do you decide which one is more appropriate?
Application of t Tests
- Is there a research question from your professional life or career specialization that can be addressed by an independent-samples t test?
- Why would a t test be the appropriate analysis for this research question?
- What are the variables and their scale of measurement?
- What is the expected outcome? (For example, “The group 1 mean score will be significantly greater than the group 2 mean score because….”)
Read Assessment 3 Context (linked in the Resources) to learn about the concepts used in this assessment.
You will use the following resources for this assessment. They are linked in the Resources.
- Complete this assessment using the DAA Template.
- Read the SPSS Data Analysis Report Guidelines for a more complete understanding of the DAA Template and how to format and organize your assessment.
- Refer to IBM SPSS Step-By-Step Instructions: t Tests for additional information on using SPSS for this assessment.
- If necessary, review the Copy/Export Output Instructions to refresh your memory on how to perform these tasks. As with your previous assessments, your submission should be narrative with supporting statistical output (table and graphs) integrated into the narrative in the appropriate place (not all at the end of the document).
You will analyze the following variables in the grades. Sav data set:
Step 1: Write Section 1 of the DAA
- Provide a context of the grades .sav data set.
- Include a definition of the specified variables (predictor, outcome) and corresponding scales of measurement.
- Specify the sample size of the data set.
Step 2: Write Section 2 of the DAA
- Analyze the assumptions of the t test.
- Paste the SPSS histogram output for gpa and discuss your visual interpretations.
- Paste SPSS descriptive output showing skewness and kurtosis values for gpa and interpret them.
- Paste SPSS output for the Shapiro-Wilk test of gpa and interpret it.
- Report the results of the Levene’s test and interpret it.
- Summarize whether or not the assumptions of the t test are met.
Step 3: Write Section 3 of the DAA
- Specify a research question related to gender and gpa.
- Articulate the null hypothesis and alternative hypothesis.
- Specify the alpha level.
Step 4: Write Section 4 of the DAA
- Paste the SPSS output of the t test.
- Report the results of the SPSS output using proper APA guidelines. Include the following:
- Degrees of freedom.
- t value.
- p value.
- Effect size.
- Interpretation of effect size.
- Means and standard deviations for each group. Mean difference.
- Interpret the results against the null hypothesis.
Step 5: Write Section 5 of the DAA
- Discuss the implications of this t test as it relates to the research question.
- Conclude with an analysis of the strengths and limitations of t-test analysis.
Because this is a psychology course, you need to format this assessment according to APA guidelines. Additional resources about APA can be found in the Research Resources in the courseroom navigation menu. Use the resources to guide your work.
- American Psychological Association. (2010). Publication manual of the American Psychological Association (6th ed.). Washington, DC: Author.
- This resource is available from the Capella University Bookstore.
The following resources are required to complete the assessment.
Data Set Instructions
These are the same instructions presented for other assessments.
- Data Set Instructions [DOCX].
Assessment Template and Output Instructions
- Data Analysis and Application (DAA) Template [DOCX].
- Use this template to complete your assessment.
- SPSS Data Analysis Report Guidelines [DOCX].
- Use this document for instructions on completing the DAA template.
- Copy/Export Output Instructions [DOCX].
- This document provides instructions for extracting output from SPSS. You will insert your output into the assessment answer template as indicated.
The resources provided here are optional and support the assessment. They provide helpful information about the topics. You may use other resources of your choice to prepare for this assessment; however, you will need to ensure that they are appropriate, credible, and valid. The XX-FP7864 – Quantitative Design and Analysis Library Guide can help direct your research, and the Supplemental Resources and Research Resources, both linked from the left navigation menu in your courseroom, provide additional resources to help support you.
Statistics Concepts and Terminology
- Assessment 3 Context [DOC].
- Read this resource for information about the statistical terminology and concepts needed to complete this assessment.
SPSS Software and Procedures
- IBM SPSS Step-By-Step Instructions: t Tests [DOCX].
- This course file provides instructions for conducting a t test using SPSS.
- In your IBM SPSS Statistics Step by Step library e-book:
- Chapter 11, “The t-Test Procedure,”
- StatSoft, Inc. (2013). Electronic statistics textbook. Tulsa, OK: StatSoft. Retrieved from http://www.statsoft.com/textbook
- Basic Statistics.
- This section contains sections on t tests.
- Skillsoft. (n.d.). Introduction to hypothesis testing and tests for means in six sigma [Video].
- View these two videos about tests for means.
- One-Sample Tests for Means.
- Two-Sample Tests for Means.
These programs have opted to provide program-specific content designed to help you better understand how the subject matter is incorporated into your particular field of study.
Order a Unique Copy of this Paper