Suppose W, X, Y and Z are i.i.d random variables with mean "mu" = -9 and standard deviation "sigma" = 6
Find the expectation and variance of each of the following estimators of "mu"
1. A = 8W + 3X - 4Y - 6Z
i got E(A) = -9 and Var(A) as 3976.... however i am having problems knowing whether i was right to convert the SD of 6 to a variance of 36?
2. B = 1/28(8W + 6X +2Y +9Z)
3. C = 33W + 4Y - 36Z
Which estimators are unbiased for "mu"?
Which estimator is the most efficient?