statistics
posted by Lee .
The mean GPA (grade point averagE. of all male students at a college is 2.77 and the mean GPA of all female students at the same college is 2.89. Suppose we take one sample of 40 male students and another sample of 50 female students from this college. What is the mean of the sampling distribution of the difference between the mean GPAs of these two samples?
how would I solve this problem.

No matter what the standard deviation of the distributions is, the mean of the GPA of both samples will be the weighted mean, which is
4/9 * 2.77 + 5/9 * 2.89.
This equals 2.84. 
The questioner doesn't want the weighted mean, she wants the mean of the difference. This is equal to the difference between the means, or 0.12.