For the situation and data described in Exercise 17.17, perform conventional multiple regression and stepwise regression analyses on the data, then compare the results of the two approaches. Use total operating revenue as the dependent variable and number of aircraft, number of employees, and number of aircraft departures as the three independent variables. The data are in file XR17017.
In exercise
The Air Transport Association has reported the following kinds of information describing 23 individual U.S. airlines: total operating revenue, number of aircraft, number of employees, and number of aircraft departures. Using data file XR17017, with y = total operating revenue (millions of dollars), x1 = number of employees, and x2 = number of aircraft departures:
We suggest that Minitab users specify alpha-to-enter as 0.05 and alphato- remove as 0.10.