Assume you already know about part b) and have the expression

In part b) you select with replacement, and therefore those are independent, and you should calculate the answer with ease.

However, in part c) they are dependent; but they still have the identical distribution. So it should not affect your calculation of . For the variance part, now you need to calculate the covariance terms .

The tricky part here is to calculate the , and the key is to recognize that as , the selections cannot be the same number. When you try to do the multiplication, it is like a square matrix missing the diagonal. And you should obtain something similar to the following: