Two Versions of Independent Samples t Test

Analyze why there are two different versions ("Equal variances assumed" and "Equal variances not assumed") of the t test on the SPSS printout and how you decide which one is more appropriate.

Unit 7 -t Tests: Theory and Logic

Reference

Warner, R. M. (2013). Applied statistics: From bivariate through multivariate techniques (2nd ed.). Thousand Oaks, CA: Sage.

OBJECTIVES

To successfully complete this learning unit, you will be expected to:

1. Evaluate research situations using the t test.

2. Identify the assumptions of the independent samples t test.

3. Analyze hypothesis testing for the t test.

4. Understand effect sizes for the t test.

5. Analyze two calculations of the t test and when they are reported.

Unit 7 Study 1- Readings

Use your Warner text, Applied Statistics: From Bivariate Through Multivariate Techniques , to complete the following:

• Read Chapter 5, "Comparing Group Means Using the Independent Samples t Test," pages 185-218.

This reading addresses the following topics:

? Research situations using the independent samples t test.

? t-test assumptions.

? Factors affecting the size of the t ratio.

? Effect sizes.

SOE Learners - Suggested Readings

Stone, E. (2010). t test, independent samples. In N. J. Salkind (Ed.), Encyclopedia of research design (pp. 1552-1556). Thousand Oaks, CA: Sage.