What method has been used to transform Model 1 to Model 2? Equations for Model 1 and Model 2 are as follows:
Model 1
Ct = 26.19 + 0.6428GNPt - 0.4398Dt + et
Model 2
Ct /GNPt = 25.92(1/GNPt)- 0.4598(Dt/GNPt)+ et
C represents Consumption expenditures
GNP represents Gross National Product
D represents defense spending
Sample is quarterly from 1960 to 1969 (time series). Test for first order serial correlation.