X.P(X) Probability P(X) (X-u) (x - 1) (x - 2)2.P(X) Number of Items Sold X 14 .20 15 .30 13 .10 16 .20 Σχ.P(X) (x - 1)?.P(X) = The variance of the probability distribution is Thard deviation than obability distribution is a​