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)= -2 Var(X) = 21 E(Y)=-4 E (Z)=-7 Var(Y) = 30 Var (Z)= 18 Compute the values of the expressions below. E(-52-1)= 0 x Х ? E (**»2-0 X+3Z 5 Var(-4Y)-2= 0 E(-4x2)= 0