* PS7.6, using DATA7-4, for the Application in Section 7.6 . First * generate the interactions between D90 and the explanatory variables. * read(data7-4) WLFP YF YM EDUC UE MR DR URB WH D90 genr D90YF = D90*YF genr D90YM=D90*YM genr D90EDUC=D90*EDUC genr D90UE=D90*UE genr D90MR=D90*MR genr D90DR=D90*DR genr D90URB=D90*URB genr D90WH=D90*WH * Estimate the most general model ols WLFP D90 YF D90YF YM D90YM EDUC D90EDUC UE D90UE MR D90MR & DR D90DR URB D90URB WH D90WH * omit variables one at a time ols WLFP D90 YF D90YF D90YM EDUC D90EDUC UE D90UE MR D90MR & DR D90DR URB D90URB WH D90WH ols WLFP D90 YF D90YF D90YM EDUC UE D90UE MR D90MR & DR D90DR URB D90URB WH D90WH ols WLFP YF D90YF D90YM EDUC UE D90UE MR D90MR DR D90DR URB D90URB WH D90WH ols WLFP YF D90YF EDUC UE D90UE MR D90MR DR D90DR URB D90URB WH D90WH ols WLFP YF D90YF EDUC UE D90UE MR D90MR DR D90DR URB D90URB WH ols WLFP YF D90YF EDUC UE D90UE MR D90MR DR D90DR URB WH * final model ols WLFP YF D90YF EDUC UE D90UE MR D90MR DR URB WH delete / all stop