COMPUTATIONAL PROBLEMS. ALL WORK MUST BE SHOWN FOR FULL

CREDIT.

9. Dr. T. Aich-Sea is a psychologist from Bowling Green University interested in studying altered time

perception. For one of her experiments, she creates two groups (with different subjects in each group).

One group of subjects does not smoke anything; while another group smokes marijuana. She waits 15

minutes and asks subjects to estimate how much time has just past (in mins). The data are shown below:

no drug vs marijuana

23 vs 20

15 vs 18

12 vs 29

20 vs 20

16 vs 34

19 vs 25

SS = 77.50 22

SS = 194.86

Use a t-test to determine if there is a difference between these two groups.

9. Dr. I. Feilgute is a psychologist interested in studying the relationship between self-esteem and

grades. Below are data indicating students' self-esteem scores and their average grades.

A. Graph these data.

B. From the results shown below, use Pearson's "r" test to determine whether there is a

significant relationship between these two variables.

C. How much variability is explained by the correlation?

D. How would you explain the possible causal relationships between these two variables?

self-esteem scores vs average grade

42 vs 63

101 vs 94

56 vs 90

31 vs 53

24 vs 72

79 vs 92

SS= 4397.50 SS= 1479.33

Assume that the SS values provided are correct (i.e., no need to re-calculate them).