Refer to Exercises 15-10 and 15-35. The file titled Flicks contains data on total U.S. box office grosses

($billion), total number of admissions (billion), average U.S. ticket price ($), and number of movie screens for the years 1987–2015 (source: National Association of Theatre Owners, www.natoonline.org/

data, Feb. 2016).

a. Construct a regression equation that uses the other variables to predict total U.S. box office grosses.

b. Produce the appropriate residual plots to determine if the linear function is the appropriate regression function for this data set.

c. Square each of the independent variables and add them to the model on which the regression equation in part a was built. Produce the new regression equation.

d. Use residual plots to determine if the quadratic model in part c alleviates the problem identified in part b.