INSTRUCTIONS: Add new part (b): give the value of and interpret the standard errorof the estimate. Add new part (c): give the predicted number of contracts sold for a month with an average contract price of $3,000, adv exp of $20,000, and per sell exp of $40,000. New part (d): give a 95% PI for the prediction of part c, based on the empirical rule of thumb and the standard error of the estimate.)

FACTS:

DataPro is a small but rapidly growing firm that provides electronic data-processing services to commercial firms, hospitals, and other organizations. For each of the past 12 months, DataPro has tracked the number of contracts sold, the average contract price, advertising expenditures, and personal selling expenditures. These dataare provided in P13_17.XLS set out below.

PROBLEM:

(a) Assuming that the number of contracts sold is the response variable, estimate a multiple regression model with three explanatory variables. Interpret each of the estimated regression coefficients and the coefficient of determinationR2 .

(b) Give the value of and interpret the standard error of the estimate.

(c) Give the predicted number of contracts sold for a month with an average contract price of $3,000, adv exp of $20,000, and per sell exp of $40,000.

(d) Give a 95% PI for the prediction of part c, based on the empirical rule of thumb and the standard error of the estimate.

The standard error of the estimates for multiple regression models are given. The number of contracts solver per month for DataPro is analyzed.