topic How do I create an interaction term with four variables in SAS Programming

How do I create an interaction term with four variables

JUMMY — Fri, 26 Apr 2019 11:46:21 GMT

I have a data of the form below. And I want to find the best model that predicts y while considering interactions as well as quadratic terms using PROC REG. How do I go about it?

data bb;
input x1 x2 y x3 x4 x5 ;

datalines;

0.442	0.672	9.2	0.1962	13.0769
0.435	0.797	11.7	-0.3038	-31.9231
0.456	0.761	15.8	-0.2038	-21.9231
0.416	0.651	8.6	-0.4038	-31.9231
0.449	0.9     23.2	0.2962	-6.9231
0.431	0.78  	27.4	-0.2038	13.0769
0.487	0.771	9.3	-0.3038	-26.9231
0.469	0.75    16	0.1962	 23.0769
0.435	0.818	4.7	0.2962	23.0769
0.48	0.825	12.5	0.0962	-1.9231
0.516	0.632	20.1	0.2962	33.0769
0.493	0.757	9.1	0.2962	33.0769
0.374	0.709	8.1	-0.3038	-26.9231
0.424	0.782	8.6	-0.5038	-26.9231
0.441	0.775	20.3	-0.4038	-31.9231
0.503	0.88    25	0.1962	8.0769
0.503	0.833	19.2	-0.1038	-17.9231
0.425	0.571	3.3	0.9962	13.0769
0.371	0.816	11.2	-0.3038	-1.9231
0.504	0.714	10.5	0.4962	28.0769
0.4	0.765	10.1	0.1962	13.0769
0.482	0.655	7.2	0.6962	51.0769
0.428	0.728	9	0.1962	23.0769
0.559	0.721	24.6	0.5962	18.0769
0.441	0.757	12.6	-0.2038	-21.9231
0.492	0.747	5.6	-0.0038	8.0769
0.402	0.739	8.7	0.1962	-1.9231
0.415	0.713	7.7	-0.5038	-31.9231
0.492	0.742	24.1	-0.1038	23.0769
0.484	0.861	11.7	-0.2038	-26.9231
0.387	0.721	7.7	-0.6038	-36.9231
0.436	0.785	9.6	-0.6038	-19.9231
0.482	0.655	7.2	0.6962	51.0769
0.34	0.821	12.3	-0.5038	-31.9231
0.516	0.728	8.9	0.0962	28.0769
0.475	0.846	13.6	-0.2038	-1.9231
0.412	0.813	11.2	-0.8038	-51.9231
0.411	0.595	2.8	0.2962	18.0769
0.407	0.573	3.2	0.3962	33.0769
0.445	0.726	9.4	0.6962	16.0769
0.291	0.707	11.9	-0.7038	-56.9231
0.449	0.804	15.4	-0.4038	-11.9231
0.546	0.784	7.4	0.1962	23.0769
0.48  	0.744	18.9	0.3962	23.0769
0.528	0.79	12.2	-0.5038	-31.9231
0.352	0.701	11	-0.9038	-26.9231
0.414	0.778	2.8	0.4962	33.0769
0.425	0.872	11.8	-0.8038	-31.9231
0.599	0.713	17.1	0.7962	28.0769
0.482	0.701	11.6	0.1962	13.0769
0.457	0.734	5.8	0.1962	3.0769
0.435	0.764	8.3	0.3962	18.0769
;
run;

proc print data=bb;
run;

Re: How do I create an interaction term with four variables

PaigeMiller — Fri, 26 Apr 2019 12:06:57 GMT

@JUMMY wrote:

I have a data of the form below. And I want to find the best model that predicts y while considering interactions as well as quadratic terms using PROC REG. How do I go about it?

You can't do this in PROC REG. You can do this easily in PROC GLM.

Re: How do I create an interaction term with four variables

JUMMY — Fri, 26 Apr 2019 12:34:17 GMT

How do I add interactions and quadratic terms using GLM?

Re: How do I create an interaction term with four variables

PaigeMiller — Fri, 26 Apr 2019 12:37:05 GMT

You put them in the model statement, for example

proc glm data=have;
    model y=x1 x2 x3 x4 x5 x1*x2 x1*x3 /* you type the rest of the interactions */
        x1*x1 x2*x2 x3*x3 x4*x4 x5*x5;
run;

or even easier, if you want all possible main effects and two way interactions and quadratic effects

proc glm data=have;
    model y = x1|x2|x3|x4|x5@2 x1*x1 x2*x2 x3*x3 x4*x4 x5*x5;
run;