試題詳解

171. The random variables X and Y have joint probability function p(x,y) for x = 0,1 and y = 0,1,2.

Suppose 3p(1,1) = p(1,2), and p(1,1) maximizes the variance of XY.

Calculate the probability that X or Y is 0.
(A) 11/25
(B) 23/50
(C) 23/49
(D) 26/49
(E) 14/25