Economics 1. Show that E(aX + bY) = QE(X) + bE(Y), where X, Y are random variables, a and b are constants. (You should specify what expectation rule(s) you use to get to the next step.) 2. Show that Var (X) = E(X2) - ux. 3. Show that Cov(X, Y) = E(XY) - Uxly, where X, Y are random variables. 4. Show that, by using Assumptions SLR. I through SLR.4, E(B, ) = B1