A company is interested in the effectiveness of radio advertising X 1 and newspaper advertising X 2 on the overall sales of its products.

A company is interested in the effectiveness of radio advertising X1 and newspaper advertising X2 on the overall sales of its products. The sales of their products and the levels of both types of media expenditure​ (all in thousands of​ dollars) for 22 locations were recorded in the following table during a one month test period.

Determine the VIF for each independent variable in the​ model, with

VIF1 and VIF2 being the VIF for X1 and X2 respectively.

Sales     Radio ads            Newspaper ads

981        0             40

1119      0             40

880        25          25

626        25          25

917        30          30

979        30          30

927        35          35

1175      35          35

887        40          25

980        40          25

1639      45          45

1570      45          45

1052      50          0

912        50          0

1334      55          25

1325      55          25

1408      60          30

1441      60          30

1528      64          35

1752      66          35

1874      69          40

1718      69          40