options ls=78 ps=49 nocenter nodate;
data nitrofen;
length treatment $8. ;
input Group_1 Group_2 @@;
/* Read in data side-by-side but output them stacked.
   The @@ sign tells SAS to keep reading pairs of numbers 
   until you run out of numbers.*/
treatment="Group_1";  response=Group_1; output;
treatment="Group_2"; response=Group_2; output;
drop Group_1 Group_2;
datalines;
15.1 6.8 14.9 7.5 14.8 8.6 14.2 8.4 13.1 8.9 12.8 8.1 15.5 9.2 15.9 9.5
;
/* Proc ttest does both the separate and pooled two independent
   sample t-tests */
proc ttest;
 class treatment;
 var response;
 title "Analysis of EX 6.75 Experiment";
 run;
 /* The npar1way procedure implements a number of nonparameteric
    analyses for one-way classified data. Here we invoke the wilcoxon
    option to get the Wilcoxon rank sums test.*/
proc npar1way wilcoxon;
  class treatment;
  var response;
  title "Wilcoxon rank sum analysis of Ex 6.75 experiment";
  run;