A group of 75 college students from a liberal arts college were randomly sampled and asked about the number of alcoholic drinks they have in a typical week. The file containing the data is linked below. The purpose of this study (Links to an external site.) was to compare the drinking habits of the students at the college to the drinking habits of college students in general. In particular, the dean of students, who initiated this study, would like to check whether the mean number of alcoholic drinks that students at his college have in a typical week differs from the mean of U. S. college students in general, which is estimated to be 4.73. Now suppose that instead of the 75 students having been randomly selected from the entire
student body, the 75 students had been randomly selected only from the business
administration classes at the college.
Address the following two issues regarding the effect of such a change in the study design:
a. Would we still be mathematically justified in using the T-test for obtaining conclusions, as
we did previously?
b. Would the resulting conclusions still address the question of interest (which, remember,
was to investigate the drinking habits of the students at the college as whole)?