An ordered sample of size 5 is drawn without replacement from an urn containing 8 white balls and 4 black balls. For j = 1,2, ... ,5 let X; be equal to 1 or 0, depending on whether the ball drawn on the jth draw is white or black. Find E[X2], a2[X2], Cov [X1, X2], Cov [X2, X3].