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 sample 100 of its members at random and monitor their working time 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 13 hours and 9 hours, respectively, find a 95% confidence interval for the true mean number of hours absent per month per employee. round your answer to four decimal places.