O RANDOM VARIABLES AND DISTRIBUTIONS Expectation and variance of a random variable 1/5 Let X be a random variable with the following probability distribution. Value x of X P(X=x) 10 0.30 20 0.05 30 0.10 40 0.30 50 0.20 60 0.05 Complete the following. (If necessary, consult a list of formulas.) (a) Find the expectation E (X ) of X. E (x) = 0 X (b) Find the variance Var(X ) of X. Var (x) = 0