The dataset GPAGender, described in Exercise D.54, contains a subset of the StudentSurvey data which also has information on totalSAT scores, GPA, and number of Piercings for those n = 343 students.
(a) Test for an association between number of Piercings and GPA using the data in GPAGender. Give the p-value and make a conclusion in context.

(b) Use multiple regression to test for an association between number of Piercings and GPA, after accounting for SAT score.

Exercise D.54

The dataset StudentSurvey, introduced on page 4, contains information on hours of Exercise per week and GPA. Here we use a slightly modified version called GPAGender which eliminates missing values (leaving n = 343 students) and codes the gender with 1 for males and 0 for females in a new GenderCode variable. This allows us to use information on gender in a regression model.