The managers of a brokerage firm are interested in finding out if the number of new clients a broker brings into the firm affects the sales generated by the broker. They sample 12 brokers and determine the number of new clients they have enrolled in the last year and their sales amounts in thousands of dollars. These data are presented in the table that follows.

Broker Clients Sales

1 48 72

2 11 37

3 42 64

4 33 55

5 15 29

6 15 34

7 25 58

8 36 59

9 28 44

10 30 48

11 17 31

12 22 38

14. What is the total variation of Sales?

15. What is the variation of Sales that can be explained by the regression equation?

What is the variation of Sales that cannot be explained by the regression equation?