Question

In the survey of a random sample of students at a university, two questions were, “How many hours per week do you usually study?” and “Have you smoked marijuana in the past six months?” An analysis of the results produced the following SPSS output:

  

A research question of interest is whether students who have smoked marijuana (group Y) in the past 6 months differ in study hours on average per week than those who have not (group N).

Which of the following is the appropriate test statistic for determining if there is a difference in average study hours per week for the two groups?

	A.
	B.
	C.
	D.

Answer 1

Here, since we have to test if there is a difference in average study hours per week for two groups (Y and N) , if the sample size is large then we can use z-test statistic and if sample size is small or less than 39 then we can use exact t-test as a test statistic.As large test statistic approximately follows normal distribution due to central limit theorem.