Question: Changing your major. A study of undergraduate computer science students examined changes in major after the first year.15 The study examined the fates of 256 students who enrolled as first-year computer science students in the same fall semester. The students were classified according to gender and their declared major at the beginning of the second year. For convenience we use the labels CS for computer science majors, EO for engineering and other science majors, and O for other majors. The explanatory variables included several high school grade summaries coded as 10 = A, 9 = A-, etc. Here are the mean high school mathematics grades for these students:

                                     Major

Gender            CS              EO             O

Males            8.68            8.35           7.65

Females         9.11            9.36           8.04

Describe the main effects and interaction using appropriate graphs and calculations.