The article referenced in the previous exercise also reported that 5.7% of high school graduates were unemployed in 2008 and 9.7% of high school graduates were unemployed in 2009. Suppose that the reported percentages were based on independently selected representative samples of 400 high school graduates in each of these 2 years.
a. Construct and interpret a 99% large-sample confidence interval for the difference in the proportions of high school graduates who were unemployed in these 2 years.
b. Is the confidence interval from Part (a) wider or narrower than the confidence interval computed in the previous exercise? Give two reasons why it is wider or narrower.