Originally Posted by
uberbandgeek6 Let W be a discrete rv with pmf f(w) = c|w-4| for w within {0,1,...,8}.
a) Find c.
b) Find E(W).
c) Find Var(W).
d) Find Var((W-4)^2).
I already found that c = 1/20, E(W) = 2.4, and Var(W) = 20.24; I'm just having problems with part (d). I split it up into:
Var((W-4)^2) = E((W-4)^4) - (E((W-4)^2))^2
I know that (W-4)^2 = W^2 - 8W + 16, but I can't really see how this would help. This there any way to go about this problem using the values that I have already found?