*  PS6.2 using DATA6-1 for Example 6.2
SAMPLE 1 20
TIME 1 1
READ(data6-1)  UNITCOST OUTPUT INPCOST
*
* The GENR command is used to generate the squares of the two independent
* variables, OUTPUT and INPCOST.
*
GENR OUTPUT2=OUTPUT**2
GENR INPCOST2=INPCOST**2
*
* Estimate the regression of UNITCOST against a constant, OUTPUT, OUTPUT2,
* INPCOST, INPCOST2.
*
OLS UNITCOST OUTPUT OUTPUT2 INPCOST INPCOST2
*
* In the previous regression, the coefficient on the variable INPCOST2 is 
* insignificant and thus, the previous model will be re-estimated with
* INPCOST2 omitted since it has no explanatory power.
*
OLS UNITCOST OUTPUT OUTPUT2 INPCOST / COEFF=B
*
*  GENERATE ESTIMATED AVERAGES TO GRAPH THE AVERAGE COST FUNCTION
*
GENR T=TIME(0)
GENR X=40+(T*5)
GENR INPCOST1=80
GENR INPCOST2=115
GENR INPCOST3=150
GENR YHAT1=B(4)+(B(1)*X)+(B(2)*X*X)+(B(3)*INPCOST1)
GENR YHAT2=B(4)+(B(1)*X)+(B(2)*X*X)+(B(3)*INPCOST2)
GENR YHAT3=B(4)+(B(1)*X)+(B(2)*X*X)+(B(3)*INPCOST3)
PRINT T X YHAT1 YHAT2 YHAT3
DELETE / ALL
STOP