the heights of men in a certain population follow a normal distribution with mean 69.7 inches and standard deviation 2.8 inches. (a) if 10 men are selected at random, what is the probability their average height is above 72 inches? (b) if exactly one man is selected at random, what is the probability his average height is above 72 inches? (c) what is the 80th percentile for the average height of 10 men? (d) what is the probability the average height of 10 men is between 70 and 71 inches?