After reading this chapter, you should be able to do the following:

• Explain when to use an independent samples t test
• Explain the logic of the independent samples t test
• Write null and research hypotheses using symbols and words for both one- and two-tailed tests
• Compute degrees of freedom and define a critical region for both one- and two-tailed tests
• Compute an independent samples t using a calculator and SPSS
• Compute and interpret an effect size (d)
• Summarize the results of the analysis using American Psychological Association (APA) style