Question:
The Tire Rack, an online distributor of tires and wheels, conducts extensive testing to provide customers with products that are right for their vehicle, driving style, and driving conditions. In addition, The Tire Rack maintains an independent consumer survey to help drivers help each other by sharing their long-term tire experiences (The Tire Rack website, August 1, 2016). The following data show survey ratings (1 to 10 scale with 10 the highest rating) for 18 high-performance all-season tires. The variable Tread Wear rates quickness of wear based on the drivers expectations, the variable Dry Traction rates the grip of a tire on a dry road, the variable Steering rates the tires steering responsiveness, and the variable Buy Again rates the drivers desire to purchase the same tire again.
a. Develop an estimated simple linear regression equation that can be used to predict the Buy Again rating given the Tread Wear rating. At the .01 level of significance, test for a significant relationship. Does this estimated regression equation provide a good fit to the data? Explain.
b. Develop an estimated multiple regression equation that can be used to predict the Buy Again rating given the Tread Wear rating and the Dry Traction rating. Is the addition of the Dry Traction independent variable significant at a = .01? Explain.
c. Develop an estimated multiple regression equation that can be used to predict the Buy Again rating given the Tread Wear rating, the Dry Traction rating, and the Steering rating. Is the addition of the Steering independent variable significant at a = .01? Explain.
Transcribed Image Text:
Tread Wear Dry Traction Buy Steering Again? Tire Sumitomo HTR A/S PO2 8.6 8.5 9.0 8.5 8.8 8.0 7.5 Goodyear Eagle Sport All-Season Michelin Pilot Sport A/S 3 Kumho Ecsta PÁ31 9.3 7.3 7.2 7.4 9.2 8.4 7.6 8.9 7.9 7.1 7.2 6.4 5.8 Firestone Firehawk Wide Oval AS BFGoodrich g-Force Super Sport A/S Yokohama AVID ENVigor Goodyear Eagle RS-A2 Hankook Ventus V2 concept2 7.1 6.4 6.6 7.1 8.7 8.7 8.4 8.0 8.3 8.4 7.9 7.9 6.5 5.8 5.4 5.2 Firestone Firehawk GT Firestone FR740 Dunlop SP Sport 7000 A/S Goodyear Eagle RS-A Bridgestone Potenza RE92A Yokohama ADVAN A83A Bridgestone Potenza RE92 Firestone Firehawk GTA-03 6.1 5.1 5.0 5.6 8.2 7.8 7.6 7.4 7.9 7.5 7.0 7.0 4.4 3.2 3.0 3.6 7.1 8.0 6.9 5.7 4.4 5.4 6.5 7.6 6.3 2.6 1.0 2.5 3.8 7.9 6.9 2.0