Q 1) If X1 ~ N(, 2) and X2 ~ N(, 2) are iid normal random variables, then what is the difference between 2 X1 and X1 + X2? Discuss both their distributions and parameters.

Q 2) Let X ~ N(100, 202). Find two values, a and b, symmetric about the mean, such that the probability of the random variable taking a value between them is 0.99.

A.90.5, 105.9

B.80.2, 119.8

C.22, 78

D.48.5, 151.5

E.90.1, 109.9