Exercise # 31: Calculating t-tests for Independent Samples

Do the example data meet the assumptions for the independent samples t-test? Provide a rationale for your answer.

If calculating by hand, draw the frequency distributions of the dependent variable, wages earned. What is the shape of the distribution? If using SPSS, what is the result of the Shapiro-Wilk test of normality for the dependent variable?

What are the means for two group’s wages earned?

What is the independent samples t-test value?

Is the t-test significant at a = 0.05? Specify how you arrived at your answer.

If using SPSS, what is the exact likelihood of obtaining a t-test value at least as extreme or as close to the one that was actually observed, assuming that the null hypothesis is true?
Which group earned the most money post-treatment?
Write your interpretation of the results, as you would in an APA-formatted journal.

What do the results indicate regarding the impact of the supported employment voca¬tional rehabilitation on wages earned?
Was the sample size adequate to detect significant differences between the two groups in this example? P

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