Suppose that the discrete random variable X has cumulative distribution function given by F(x) =    0 if x < 1 1 3 if 1 ≤ x < 4 3 1 2 if 4 3 ≤ x < 3 2 3 4 if 3 2 ≤ x < 9 5 1 if x ≥ 9 5 Find the possible values and the probability mass function X.