For the situation and variables in Exercise 17.17, use data file XR17017 and generate a correlation matrix for these independent variables: number of aircraft, number of employees, and number of aircraft departures. Examine the correlation matrix and comment on the possible presence of multicollinearity.
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: