44. The U.S. Postal Service offers shipping via flat rate boxes in three sizes: small, costing $7.90, medium, costing $14.35, and large, costing $19.95. Let X1, X2, and X, denote the number of boxes of these types sent from a particular post office on a certain day. Suppose that 41 = 25, H2 = 40, 4z = 32,01 = 8,02 = 10, 03 = 12, P12 = -35, P13 = .20, P23 .28. Determine the expected total revenue from shipping flat rate boxes on this day and the standard deviation of total revenue. =