My outcome variable is categorical (4 categories: very low, low, moderate, high), and my predictor variables are categorical. One has 3 categories and is year (year1, year2, year3). Year was not included in the class statement. The second is yes/no. And then it is controlled for other covariates. I ran proc glimmix with an interaction term between the two and the interaction term is significant. I am trying to understand what this interaction means from the estimate output and therefore am trying to look at the interaction plot but what I ran did not work. Any help in interpreting this interaction term (via interaction plots if necessary) would be great. Thank you!
proc sort data=data;
by predictor year;
run;
proc means data=data noprint;
by predictor year;
var outcome;
output out=meaned mean=mmoutcome;
run;
proc plot data=meaned;
plot mmoutcome*predictor=year;
run;
SAS Output predictor Estimate Standard Error DF t Value Pr > |t|
year*predictor 0 0.4159 0.1688 765 2.46 0.0140
year*predictor 1