1) What would be the most appropriate statistical test for a research project examining whether recidivism scores from 20 juveniles changed after participating in a cognitive-behavior program, in comparison to their scores prior to participating in the program? a) t test for the correlation coefficient b) t test for dependent means c) t test for independent samples d) t test for related populations

2) For a t test for dependent means, how do you calculate the degrees of freedom? a) n -1, where n is the number of pairs of observations b) n1 -1 + n2 -1 c) n1 -1 d) n1 + n2 3) When do you use table B.2 in the back of your textbook? a) to set the level of risk b) to determine the obtained t test value c) to determine the critical t test value d) none of the above

4) The data below are from students who participated in Respect Your Classmate educational program. The pretest is the number of times a student was respectful to a classmate before s/he participated in the program. The posttest is the number of times a student was respectful to a classmate after s/he participated in the program. You are interested in determining if the posttest scores are significantly different from the pretest scores (Hint: assume a one-tailed test). USE THIS INFORMATION TO ANSWER QUESTIONS 4 THROUGH 6. Pretest 3 Posttest 4 2 7 4 6 2 4 1 5 5 8 6 9 3 8 2 6 3 7

Calculate the degrees of freedom. a) -9 b) 10 c) 20 d) 9

5) Calculate the t value a) 7.80 b) 77.80 c) -9.89 d) -5.90 6) Interpret your results.

a) The null hypothesis must not be rejected. It can be concluded that there is no significant difference between the two sets of scores and the program was a failure. b) The null hypothesis must be rejected. It can be concluded that there is a significant difference between the two sets of scores and the program was successful. c) No interpretation of the results is possible because the obtained value is equal to .05. d) No interpretation of the results is possible because the sample is not big enough.

7) USE THE INFORMATION BELOW TO ANSWER QUESTIONS 7 AND 8. The results from a t test for dependent means is: t(55) = 1.13, p<.05. How many subjects were there in the study? a) 50 b) 56 c) 54 d) cannot be determined

8) The obtained t statistic was and it was a) 1.13, not significant b) 1.13, significant c) 1.673, not significant d) 1.673, significant

9) In a two-tailed test, you can reject the null hypothesis: a) whenever there is a difference between the obtained t value and the critical value b) only if the difference between the obtained t value and the critical value is a negative number c) whenever the obtained t value is more extreme than the critical value d) whenever the critical value is 0

10) What is the difference between a t test for independent samples and a t test for dependent samples? a) A t test for independent samples compares two unrelated groups, while a t test for dependent samples is used to compare scores from the same subjects under two different conditions b) A t test for independent samples compares two related groups, while a t test for dependent samples is used to compare scores from the same subjects under the same conditions c) p < .05 in an independent sample and p > .05 in a dependent sample d) there is no difference between the two types of t test