Let X be a random variable with the following probability distribution. Value x of X P(X=x) 30 0.10 40 0.30 50 0.05 60 0.10 70 0.45 Complete the following. (If necessary, consult a list of formulas. ) a) Find the expectation E (X) of X. E(X) = 1 X 5 ? (b) Find the variance Var(X) of X. Var(X) = 1