Final answer:
The question does not provide enough information to determine if older men are shorter than younger men.
Step-by-step explanation:
The question asks if older men are shorter than younger men. In order to answer this question, we need information about the mean height of older men. However, the only information provided is about the mean height of U.S. men, which is 69.4 inches. Unfortunately, this information is not specific enough to determine whether older men are shorter than younger men. We would need additional data about the mean height of older men to make a comparison.