Of nine executives in a business firm, four are married, three have never married and two are divorced. Three of the executives are to be selected for a promotion. Let Y1 denote the number of married executives and Y2 be the number of never-married executives among the three selected for promotion. Assuming that the three are randomly selected from the nine available.
a. Find the joint PMF for y1 and y2
b. Find the marginal probability distribution of y1
c. If we let y3 denote the number of divorced executives among the three selected for promotion. Find P(y3 =1 | y2 = 1)
d. Are Y1 and Y2 independent? Why?
e. Find cov(Y1,Y2). Does the sign surprise you? Why?