The Skelton Manufacturing Company recently did a study of its customers. A random sample of 50 customer accounts was pulled from the computer records. Two variables were observed:

y = Total dollar volume of business this year x = Miles customer is from corporate headquarters The following statistics were computed:
yn = 2,140.23 - 10.12x sb1 = 3.12

a. Interpret the regression slope coefficient.

b. Using a significance level of 0.01, test to determine whether it is true that the farther a customer is from the corporate headquarters, the smaller the total dollar volume of business.