In Problem 13.6 on page 470, you used the total worldwide revenue ($ millions) and full time voluntary turnover (%) data stored in Best Companies to predict the number of full time jobs added. Using the results from that problem,

a. Construct a 95% confidence interval estimate of the population slope between the number of full time jobs added and total worldwide revenue.

b. At the 0.05 level of significance, determine whether each independent variable makes a significant contribution to the regression model. On the basis of these results, indicate the independent variables to include in this model.