A 2012 survey conducted by Idea Works provided data showing the percentage of seats available when customers try to redeem points or miles for free travel. For each airline listed, the column labeled 2011 Percentage shows the percentage of seats available in 2011 and the column labeled 2012 shows the corresponding percentage in 2012 (The Wall Street Journal, May 17, 2012).

a. Develop a scatter diagram with 2011 Percentage as the independent variable.
b. What does the scatter diagram developed in part (a) indicate about the relationship between the two variables?
c. Develop the estimated regression equation.
d. Test for a significant relationship. Use α = .05.
e. Did the estimated regression equation provide a good fit?
f. Construct a residual plot. Comment on the shape of the plot as well as any unusual lookingpoints.

Airline 2011 Percentage 2012 Percentage Air Berlin Air Canada Air France, KLM AirTran Airways Alaska Airlines American Airlines 96.4 82.1 65.0 47.1 64.3 62.9 100.0 55.7 87.1 59.3 45.7 79.3 British Airways Cathay Pacific Delta Air Lines Emirates GOL Airlines (Brazil) 66.4 27.1 32.9 100.0 70.7 79.3 ria 63.6 JetBlue LAN (Chile) Lufthansa, Swiss, Austrian Qantas SAS Scandinavian 86.4 92.1 57.9 100.0 75.7 85.0 52.9 90.7 99.3 Singapore Airlines Southwest Turkish Airways United Airlines US Airways Virgin Australia 38.6 90.0