11. A European growth mutual fund specializes in stocks from the British Isles, continental Europe, and Scandinavia. The fund has over 400 stocks. Let x be a random variable that represents the monthly percentage return for this fund. Suppose x has mean = 1.4% and standard deviation = 0.8%.

(a) After 9 months, what is the probability that the average monthly percentage return x will be between 1% and 2%? (Round your answer to four decimal places.)

(b) After 18 months, what is the probability that the average monthly percentage return x will be between 1% and 2%? (Round your answer to four decimal places.)

(c) If after 18 months the average monthly percentage return x is more than 2%, would that tend to shake your confidence in the statement that = 1.4%? If this happened, do you think the European stock market might be heating up? (Round your answer to four decimal places.) P(x > 2%) =

12. The taxi and takeoff time for commercial jets is a random variable x with a mean of 8.5 minutes and a standard deviation of 3.4 minutes. Assume that the distribution of taxi and takeoff times is approximately normal. You may assume that the jets are lined up on a runway so that one taxies and takes off immediately after the other, and that they take off one at a time on a given runway.

(a) What is the probability that for 36 jets on a given runway, total taxi and takeoff time will be less than 320 minutes? (Round your answer to four decimal places.)

(b) What is the probability that for 36 jets on a given runway, total taxi and takeoff time will be more than 275 minutes? (Round your answer to four decimal places.)

(c) What is the probability that for 36 jets on a giv