Posted by Ashley on .
The psychologists are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living before and after group therapy. Therefore, the psychologists have randomly selected 8 depressed clients in a 6week group therapy program. Use the five steps of hypothesis testing to determine whether the observed differences in numbers of activities of daily living (shown below) obtained before and after therapy are statistically significant at the .05 level of significance (and, for practice, at the .01 level).
ClientBefore therapyAfter therapy
A1217
B715
C1012
D1321
E916
F818
G1417
H118
#1You calculated the standard deviation of the means. What was the standard deviation?
3.78
2.06
1.49
1.01
#2 You estimated the variance of the population of difference scores from the sample of difference scores. What the population variance?
20.32
17.71
15.75
18.98

Statistics 
MathGuru,
Try a correlated groups (or dependent groups) ttest for this problem.