63 Questions 63 and 64 refer to the following information. The independent random variables X and Y are defined by the following probability distribution tables. X A 3 6 P(X) Y .6 2 5 .3 1 2. 1 7 P(Y) . 1 2 13 .4 Determine the mean of X+Y (a) 7.2 (b) 8.4 (c) 5.1 (d) 9 (e) 4.3 64 Determine the standard deviation of 4X: (a) 39.84 (b) -2.76 (c) 1.58 (d) 10.62 (e) None of these