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

**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 vocational rehabilitation on wages earned?
- 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**

- Do the example data meet the assumptions for the paired samples t -test? Provide a rationale for your answer.
- 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?
- What are the means for the baseline and posttreatment affective distress scores, respectively?
- What is the paired samples t -test value?
- Is the t -test significant at α = 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 as or as close to the one that was actually observed, assuming that the null hypothesis is true?
- On average, did the affective distress scores improve or deteriorate over time? Provide a rationale for your answer.
- Write your interpretation of the results as you would in an APA-formatted journal
- What do the results indicate regarding the impact of the rehabilitation on emotional distress

levels? - What are the weaknesses of the design in this example?