According to data from the Organization for Economic Cooperation and Development, the average U.S. worker takes 16 days of vacation each year (The Wall Street Journal, June 2 0 , 2007). Assume that these data were based on a sample of 225 workers and that the sample standard deviation is 12 days.

a. Construct a 95% confidence interval of the population mean.

b. At a 95% confidence level, can w e conclude that the average U.S. worker does not take 14 days of vacation each year? P-69