RANDOM VARIABLES AND DISTRIBUTIONS Rules for expectation and variance of random variables Suppose that X, Y, and Z are jointly distributed random variables, that is, they are defined on the same sample space. Suppose that we also have the following. E(X) =0 E(Y) =-8 E(Z)=7 Var(X) =15 Var(Y) =40 Var(Z) =49 Compute the values of the expressions below. E(-4Z-5) = 0 (-27+5X) X ? - 3 Var(2Y-4) = 0 E(-4Y2) - 0 M 888 DII DD F2 F3 F4 F6 F6 F7 FO F10 % & ik Ne W# 4 5 6 8 9 O W E R T Y U O S D F G H K