A health psychologist knew that corporate executives in general have an average stress inventory score of 80 with a standard deviation of 12, and that the scores obtained using the inventory are distributed normally. In order to learn whether exercise is associated with a difference in stress scores among corporate executives, the psychologist measured the stress of a sample of 25 exercising executives and found them to have a mean score of 72.

Which is closest to the z-score observed for this sample's mean?

A) -3

B) - 1.5

C) 0

E) 3

D) 1.5

Do executives who exercise have different anxiety scores than the general population of executives? Use the .05 significance level (5%). Which of the following is the correct NULL HYPOTHESIS in this instance?

a) general= research

b)generalresearch

c) general>research

d)general

Do executives who exercise have different anxiety scores than the general population of executives? Use the .05 significance level (5%). Which of the following is the correct RESEARCH HYPOTHESIS in this instance?

a) general= research

b)generalresearch

c) general>research

d)general