Hi i was just wondering if the following was correct Given X and Y, Z has the mean and Variance Mean: 15 Variance:25
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Originally Posted by 1234567 Hi i was just wondering if the following was correct Given X and Y, Z has the mean and Variance Mean: 15 Variance:25 Look fine. Why would you doubt it?
can i ask how you got the mean and variance for Z
Originally Posted by anon18 can i ask how you got the mean and variance for Z From standard theorems: E(Z) = E(X - 4Y + 1) = E(X) - 4 E(Y) + 1. Var(Z) = Var(X - 4Y + 1) = Var(X) + 4^2 Var(Y)
thanks...so how would you work out the correlation between X and Z and between Y and Z. using correlation(X,Z)=cov(X,Z)/sqrt[var(x)var(Z)] how would you work out the cov(X,Z)
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