Use the Following Information for Questions

Multiple Choice

Use the following information for questions:
When people get married for the first time, the husband is, on average, 2 years older than the wife. The standard deviation of the difference in age is roughly 2.5 years. Suppose it is reasonable to assume that the distribution of the difference in age between the husband and the wife is normal. Twelve recently married couples (all first marriages) are to be selected and the average difference in age is to be calculated.
-What is the standard deviation of the sampling distribution of the sample mean difference in age between the husband and the wife?

A) 0.208
B) 0.72
C) 2
D) 2.5