Suppose a large labor union wishes to estimate the mean number of hours per month a union member is absent from work. The union decides to sammple 348 of its members at random and monitor the working time of each of them for 1 month. At the end of the month the total number of hours absent from work is recorded for each employee . if the mean and standard deviation of the sample are x = 7.5 hours and s = 3.5 hours, find a 99% confidence interval for the true mean number of hours a union member is absent per month. Round to the nearest thousandth. A) 7.5 ± .258
B) 7.5 ± .186
C) 7.5 ± .026
D) 7.5 ± .483