A Sample of 25 Different Payroll Departments Found That the Employees

Multiple Choice

A sample of 25 different payroll departments found that the employees worked an average of 310.3 days a year. Assume a population standard deviation of 23.8 days. What is the 90% confidence interval for the
Average days worked, $\mu$ of all payroll departments?

A) $301.0 < \mu < 319.6$
B) $298.0 < \mu < 322.6$
C) $302.4 < \mu < 318.2$
D) $314.1 < \mu < 316.8$