Question: Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relationship between the number of client contacts and the dollar amount of sales. To document this assertion, Mr. McWhinney gathered the following sample information. The X column indicates the number of client contacts last month, and the Y column shows the value of sales ($ thousands) last month for each client sampled.

Number of Sales Number of Sales

Contacts, ($ thousands), Contacts, ($ thousands),

X Y X Y
14 24 23 30
12 14 48 90
20 28 50 85
16 30 55 120
46 80 50 110

a. Determine the regression equation.

b. Determine the estimated sales if 40 contacts are made.