Suppose the heights of 18-year-old men are approximately normally distributed, with mean 72 inches and standard deviation 5 inches.

(a) What is the probability that an 18-year-old man selected at random is between 71 and 73 inches tall? (Round your answer to four decimal places.)

(b) If a random sample of seven 18-year-old men is selected, what is the probability that the mean height x is between 71 and 73 inches? (Round your answer to four decimal places.)