11.75 Differences in means.
Verify that the coefficient of in each part of the previous exercise is equal to the mean for Group B minus the mean for Group A. Do you think that this will be true in general? Explain your answer.
11.75
(a) , which is the slope for . (b) , which is the slope for . (c) , which is the slope for . Yes, it is true in general as long as is an indicator variable with values 0 and 1.