Subject: Re: Random var is defined...
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

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