HLT 362V Statistics Exercise 31 and 32

Name: _______________________________

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?