A company has offices in two different countries. Suppose that the average age (in years) of the employees at location A is 40.0 with a standard deviation of 5.5, and the average at location B is 36.0 with a standard
deviation of 6.3.
Every month, the company takes separate random samples of 50 employees from location A and 75 from
location B for a survey. Each time, they look at the difference in the mean age sampled from each location
(CA - DB).
What are the mean and standard deviation (in years) of the sampling distribution of T A - ib?