Predicting substance abuse. What factors predict substance abuse among high school students? One study designed to answer this question collected data from 89 high school seniors in a suburban Florida high school.5 One of the response variables was marijuana use, which was rated on a four-point scale. A multiple regression analysis used grade point average (GPA), popularity, and a depression score to predict marijuana use.
The results were reported in a table similar to this:
(a) State the null and alternative hypotheses that are tested by each of the t statistics. Give the results of these signi?cance tests.
(b) Interpret the sign of each of the regression coef?cients given in the table.
(c) In the expression F(3, 85), what do the numbers 3 and 85 represent?
(d) State the null and alternative hypotheses that are tested by the F statistic. What is the conclusion?
(e) Each of the variables in this analysis was measured by having the students complete a questionnaire. Discuss how this might affect the results.
(f) How well do you think that these results can be applied to other populations of high school students?