A textbook publisher for books used in business schools believes that the number of books sold is related to the number of campus visits to decision makers made by their sales force. A sampling of the number of sales calls made and the number of books sold is shown in the following table. # OF SALES CALLS MADE # OF BOOKS SOLD
25 375
15 250
25 525
45 825
35 550
25 575
25 550
35 575
25 400
15 400

Sales Calls Made Versus Number of Books Sold Summary
Measure Value
Error Measures
Cummulative For. Error = 0
MAD = 72.5
MSE = 5550.986
Standard Error (denom=n=8) = 83.299
MAPE = 0.163
Regression Line
Books Sold = 104,605
+ 14.737 * Sales Calls Made
Statistics

What percent in the variation of the variable Books Sold is explained by the value of the variable Sales Calls Made?
A) 86.5%
B) 83.3%
C) 74.8%
D) 72.5%