Let b>a and let X-uniform(a,b) . Prove Var(X) = Var(X)= E(X^2)-E(X)^2 =integral from a to b of I know E(X)= (b-a)/2 so E(X^2) must be wrong as when I subtract I do not get required Var(X).
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Originally Posted by Duke Let b>a and let X-uniform(a,b) . Prove Var(X) = Var(X)= E(X^2)-E(X)^2 =integral from a to b of I know E(X)= (b-a)/2 so E(X^2) must be wrong as when I subtract I do not get required Var(X). Consider this:
Last edited by Plato; Dec 3rd 2011 at 11:17 AM.
but surely there is a missing factor of 1/(b-a) on the RHS
Originally Posted by Duke but surely there is a missing factor of 1/(b-a) on the RHS Yes. I edited it.
So does it work out correctly for you ?
Originally Posted by Duke So does it work out correctly for you ?
Last edited by Plato; Dec 3rd 2011 at 12:03 PM.
so you are saying b^3-a^3=(b-a)(b+a)^2
Originally Posted by Duke so you are saying b^3-a^3=(b-a)(b+a)^2 NO. You have two mistakes in the OP.
Originally Posted by Duke Let b>a and let X-uniform(a,b) . Prove Var(X) = The pdf is The expectation is . Then . Now what is
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