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. Please write down the regression equation.

15. The individual value prediction for the amount of sales (in $1,000s) for a person who brings 25 new clients into the firm is ________.

16. What is the total variation of "Sales"?

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

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

19. What percentage of the variation in "Sales" is explained by its regression on "number of new clients"?

20. What is the coefficient of determination?