A tele marketing wants to know if sales go up as they call more people per day but spend less time per call. The following is data from nine randomly selected days. The information is the number of calls the salesperson makes in a day and the total amount of sales (in thousands of dollars).
Calls 25 29 33 37 43 48 52 55 67
Sales 3.7 4.2 4.2 5.0 4.7 5.3 4.9 5.6 5.9
a) Calculate ∑X, ∑X^2, ∑Y, ∑Y^2, ∑XY
b) Calculate SSxx, SSyy, and SSxy