4 Jointly Distributed Random Variables Suppose that pXY (x, y), the joint probability mass function of X and Y, is given by pXY (0, 0) = 0.4, pXY (0, 1) = 0.2, pXY (1, 0) = 0.1, pXY (1, 1) = 0.3. What is the marginal distribution of X, pX? What is the marginal distribution of Y, PY ? Calculate the conditional probability mass function of X given Y = 1. Use the total probability rule to compute expectation of X. Problem 5 Sum of Random Variables Suppose n balls are randomly selected from an urn containing N balls, of which m are white. The balls are selected one at a time and put back into the urn after each selection. Find the expected number of white balls selected, denoted by X