Suppose a Large Labor Union Wishes to Estimate the Mean $\bar { x } = 9.5$

Multiple Choice

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 426 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 $\bar { x } = 9.5$ hours and $s = 2.2$ 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) $9.5 \pm .106$
B) $9.5 \pm .013$
C) $9.5 \pm .274$
D) $9.5 \pm .185$