The chapter introduction gave the accompanying data on the percentage of those eligible...

The chapter introduction gave the accompanying data on the percentage of those eligible for a lowincome subsidy who had signed up for a Medicare drug plan in each of 49 states (information was not available for Vermont) and the District of Columbia (USA Today, May 9, 2006).

a. Compute the mean for this data set.

b. The article stated that nationwide, 24% of those eligible had signed up. Explain why the mean of this data set from Part (a) is not equal to 24. (No information was available for Vermont, but that is not the reason that the mean differs—the 24% was calculated excluding Vermont.)