A study of undergraduate computer science students examined changes in major after first year. The study examined 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 semester. For convenience we use 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: Table 1: Mean HS mathematics grades Major Gender CS EO Males 8.68 8.35 7.65 Females 9.11 9.36 8.04 Describe the main effects and interactions using appropriate graphs and calculations.