Let X be a random variable with the following probability distribution. Value x of X P(X-x) 0 0.25 10 0.05 20 0.10 30 0.30 40 0.30 Complete the following. (If necessary, consult a list of formulas.) (a) Find the expectation E (X) of X. X E(X) = 1 (b) Find the variance Var(X) of X. Var (x) =