Simulations in SAS

Simulate Poisson Data

/* Tabulate counts and plot data */
%let N=150;
data CountData;
array xx1{&N} _temporary_;
array xx2{&N} _temporary_;
call streaminit(1);
/* simulate fixed effects */
do i=1 to &N;
xx1{i}=rand("Uniform");
xx2{i}=rand("Normal", 0 , 0.5);
end;
/*Simulate POISSON Model */
do i=1 to &N;
x1=xx1{i};
x2=xx2{i};
/*linear model with the following parameters --> intercept = 2 / x1 = -4 / x2 = 1 */
eta=1-1*x1+1*x2; /* linear predictor */ 
mu=exp(eta); /* link function used to connect eta (linear predictor) to the response variable via simulation*/ 
count=rand("Poisson", mu);
output;end;run;
proc freq data=CountData noprint;tables count / out=CountMinMax;run;
data _null_;set CountMinMax end=eof;
if _N_=1 then call symputx('minCount', count);
if eof then call symputx('maxCount', count);
run;
%put min=&minCount max=&maxCount;
/* Visualize the data */
title 'Frequency Plot of Count Dataset';
proc sgplot data=CountData;
vbar count;
xaxis display=(nolabel);
yaxis display=(nolabel);
run;
title;