5 (20 points) No answer yet Assume that X1 and X2 are independent random variables such that P(X1 = 1) = P(X1 = -1) = ,, P(X2 = 1) = p, and P(X2 = -1) = 1 - p for a fixed real number p E (0, 1). Prove that that the random variables X2 and X1 . X2 are independent