14. Vital Statistics: Heights of Men The heights of 18-year-old men are approximately normally distributed, with mean 68 inches and standard devi. ation 3 inches (based on information from Statistical Abstract of the United States, 112th edition). (a) What is the probability that an 18-year-old man selected at random is between 67 and 69 inches tall? (b) If a random sample of nine 18-year-old men is selected, what is the probability that the mean height x is between 67 and 69 inches?InCly ) the person has a case of excess insulin. 16. 1 Medical: White Blood Cells Let x be a random variable that represents white blood cell count per cubic milliliter of whole blood. Assume that x has a distribution that is approximately normal, with mean u = 7500 and estimated standard deviation o = 1750 (see reference in Problem 15). A test result of x