/******************************************************************************
 * Programme : Prueba de permutación para la comparación de medias
 * Reference : PRUEBADEA1
 * Source    : https://www.wearecas.eu/en/sampleCode/PRUEBADEA1
 ******************************************************************************/

/* --- BLOC 1 --- */
data trauma;
	input state $ kcal;
	datalines;
0 19
0 20
0 20
0 21
0 21
0 21
1 22
0 23
0 23
1 23
1 25
1 26
1 30
1 38
1 39
;

/* 0 = Non-Trauma, 1 = Trauma */

/* --- BLOC 2 --- */
proc ttest data=trauma;
	class state;
	*may need to convert School to numeric;
	var kcal;
run;

/* --- BLOC 3 --- */
ods output off;
ods exclude all;

/* --- BLOC 4 --- */
proc iml ;
	use trauma;
	read all var{state kcal} into x;
	*change varibale names here ... make sure it   is   class then var ... in that order.;
	p=t(ranperm(x[, 2], 5000));
	*Note that the "1000" here is the number of permutations. ;
	paf=x[, 1]||p;
	create newds from paf;
	append from paf;
	quit;

/* --- BLOC 5 --- */
ods output conflimits=diff;

/* --- BLOC 6 --- */
proc ttest data=newds plots=none;
	class col1;
	var col2 -  col1001;
run;

/* --- BLOC 7 --- */
ods output on;
ods exclude none;

/* --- BLOC 8 --- */
proc univariate data=diff;
	where method="Pooled";
	var mean;
	histogram mean;
run;

/* --- BLOC 9 --- */
data numdiffs;
	set diff;
	where method="Pooled";

	if abs(mean) >=7.8089;
	*you will need to put the observed difference you got from t test above here.  note if you have a one or two tailed test.;
run;

/* --- BLOC 10 --- */
proc print data=numdiffs;
	where method="Pooled";
run;