A company maintains three offices in a certain region, each staffed by two employees. Information concerning yearly salaries (1000s of dollars) is as follows:

Office 1 1 2 233 Employee 1 2 3 456 Salary 29.7 33.6 30.2 33.6 25.8 29.7

a. Suppose two of these employees are randomly selected from among the six (without replacement). Determine the sampling distribution of the sample mean salary X.

b. Suppose one of the three offices is randomly selected.

Let X1 and X2 denote the salaries of the two employees.

Determine the sampling distribution of X.

c. How does E(X) from parts

(a) and

(b) compare to the population mean salary ?