4 5 6 Let X be a random variable with the following probability distribution. Value x of X P (X = x) 40 0.30 50 0.10 60 0.25 70 0.05 80 0.25 90 0.05 Complete the following. (If necessary, consult a list of formulas.) (a) Find the expectation E (X ) of X. X E(X ) = 0 (b) Find the variance Var(X ) of X. Var(X ) =