TIME 1965 4
SAMPLE 1965.1 1970.4
READ (PROFITS.txt) PERIOD PROFITS SALES 
GEN1 N=$N
* Create seasonal dummy variables
MATRIX QD=SEAS(N,4)
GENR QD2=QD:2
GENR QD3=QD:3
GENR QD4=QD:4

* Estimation with seasonal dummy variables   (Gujarati, Equation (15.10.2))
OLS PROFITS QD2 QD3 QD4 SALES 

* Test for the significance of seasonal factors
TEST  
  TEST QD2=0
  TEST QD3=0
  TEST QD4=0
END  

* Restricted Estimation    (Gujarati, Equation (15.10.3))
OLS PROFITS QD2 SALES
STOP