Final answer:
The empirical rule indicates that only 0.3% of American men aged 18 to 24 will be outside the range of 60.5 to 75.5 inches tall, based on a normal distribution with a mean height of 68 inches and a 2.5-inch standard deviation.
Step-by-step explanation:
The height of American men aged 18 to 24 is approximately normally distributed with a mean of 68 inches and a standard deviation of 2.5 inches. Using the empirical rule, we can determine that about 68% of these young men will have heights within one standard deviation of the mean (65.5 inches to 70.5 inches), 95% within two standard deviations (63 inches to 73 inches), and 99.7% within three standard deviations (60.5 inches to 75.5 inches). Since only about 0.3% fall outside of this range, very few young men will be shorter than 60.5 inches or taller than 75.5 inches.