Thread: Word problem dont know where to begin
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Old January 2nd, 2009, 05:44 PM
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Quote:
Originally Posted by nzmathman View Post
a) The mean,
b) For any two random variables X and Y, E(X + Y) = E(X) + E(Y) and Var(X + Y) = Var(X) + Var(Y)


c) For this question, use the rules E(aX + bY) = aE(x) + bE(Y) and Var(aX + bY) = a^2Var(X) + b^2Var(Y)
Well, more specifically, any two independent random variables X and Y. If they are not independent, there will be a leftover covariance term in there...
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