Date: Tue, 23 Sep 1997 15:28:53 -0400

From: Alex Bogomolny

Dear Susan:

You have

E[(X-1)^2]=10 and

E[(X-2)^2]=6

This means that

E[X^2 - 2X + 1] = 10, and

E[X^2 - 4X + 4] = 6

Subtract second from the first:

E[2X - 3] = 4, or

2E[X] - 3 = 4. Hence E[X] = 7/2.

Would you be able to find the variance now?

Regards

Alexander Bogomolny