Questions 8 and 9 refer to the following problem setting: Suppose Y1 and Y2 are two independent Normal random variables with means 50 and 100 respectively, and standard deviations 10 and 20 respectively. Let Z = 3Y1 + 2Y2 + 5: . What is the variance of the random variable Z ? (A) 1100 (B.) 2505 (0.) 2500 [D.) 1105 (13.) 5005 . What is the mean of the random variable Z? (A) 155 (B) 150 (0.) 350 (D.) 100 (E) 355