The link below give out Stepwise Regression.
https://communities.sas.com/t5/SAS-Programming/How-to-do-Regression-on-Broken-Turning-Line/m-p/83226...
I have one quest. Say I have dataset below. Surely I can have code on two-step regression. But how to tell(what criteria to tell) two-step
is better than one-step regression?! Thanks,
%let slope1=-2; %let slope2=5; %let turner=90;
data indata;
do i=1 to 100;
if i<&turner. then y=5*ranuni(i)+i*&slope1.;
else y=10*ranuni(i)+i*&slope2.-&turner.*&slope2.+&turner.*&slope1.;
output;
end;
run;quit;
ods listing gpath="%sysfunc(getoption(work))";
proc sgplot data=indata;
scatter x=i y=y;
run;quit;
