Question 12 (5 points) According to sample data from the OECD, the average U.S. worker takes 23.3 days of vacation each year. Assume a sample standard deviation of 40 and a sample size of 45. Construct a 99% confidence interval for the population mean. Note: Round intermediary calculation to the 3rd decimal place (thousandths). Choose the closest correct answer. * tdf,a/2 vo where df = n-1, and alpha = 1-C.I. dr 0.20 0.10 0.05 0.025 0.01 0.005 42 0850 0.850 0850 0.850 0.850 1.302 1.302 1.301 1.682 1.681 1680 1.679 1.679 2018 2017 2015 2014 2013 2418 2416 2414 2412 2410 2.698 2.695 2692 2.690 2.687 45 1.301 46 1.300 a) [4.93, 41.77] b) (8.23, 38.55) c) (7.25, 39.35) d) (8.91, 37.69]