Question

A study of undergraduate computer science students examined changes in major after the first year. The study examined the fates of 256 students who enrolled as first-year 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

Calculate the marginal mean for each major and each gender. Round your answer to 3 decimal places.
CS Marginal Mean 1
EO Marginal Mean 2
0 Marginal Mean 3
Male Marginal Mean 4
Female Marginal Mean 5

Compute the female - male difference for each major. Are they similar? Do any of these differences indicate an interaction?

The difference is similar for CS and EO but more than twice as big for O, indicating an interaction. The difference is similar for EO and O but more than twice as big for CS, indicating an interaction.    
The difference is similar for CS and O but more than twice as big for EO, indicating an interaction. The difference is similar for all three indicating no interactions.

Answer 1