**HLT 362V Statistics Exercise 31 and 32**

**Exercise 31 – Calculating t-tests for Independent Samples**

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

**2. **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?

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

**4.** What is the independent samples t -test value?

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

**6.** 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?

**7.** Which group earned the most money post-treatment?

**8. **Write your interpretation of the results as you would in an APA-formatted journal.

**9.** What do the results indicate regarding the impact of the supported employment vocational

rehabilitation on wages earned?

**10. **Was the sample size adequate to detect significant differences between the two groups in this

example? Provide a rationale for your answer.

**Exercise 32 Calculating t-tests for Paired (Dependent) Samples**

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

**2. **If calculating by hand, draw the frequency distributions of the two variables. What are the shapes of the distributions? If using SPSS, what are the results of the Shapiro-Wilk tests of normality for the two variables?

**3. **What are the means for the baseline and posttreatment affective distress scores, respectively?

**4.** What is the paired samples t -test value?

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

**6.** If using SPSS, what is the exact likelihood of obtaining a t- test value at least as extreme as or as close to the one that was actually observed, assuming that the null hypothesis is true?

**7.** On average, did the affective distress scores improve or deteriorate over time? Provide a rationale for your answer.

**8. **Write your interpretation of the results as you would in an APA-formatted journal.

**9.** What do the results indicate regarding the impact of the rehabilitation on emotional distress

levels?

**10.** What are the weaknesses of the design in this example?