E RANDOM VARIABLES AND DISTRIBUTIONS Expectation and variance of a random variable Let X be a random variable with the following probability distribution. Value X of X P ( X =x) -2 0.25 -1 0.20 0 0.20 1 0.30 2 0.05 Complete the following. (If necessary, consult a list of formulas.) (a) Find the expectation E (X) of X. E(X) = I X 5 P (b) Find the variance Var(X) of X. Var (X) = [