Suppose x has a distribution with = 11 and = 8.

(a) If a random sample of size n = 39 is drawn, find _x, _x and P(11 x 13). (Round _x to two decimal places and the probability to four decimal places.)

P(11 x 13) =

(b) If a random sample of size n = 57 is drawn, find _x, _x and P(11 x 13). (Round _x to two decimal places and the probability to four decimal places.)

_x =

P(11 x 13) =