*process source attributes xref;
 stddev: proc options(main);
   declare a(10) float init(1,2,3,4,5,6,7,8,9,10);
   declare stdev float;
   declare i fixed binary;

   stdev=std_dev(a);
   put skip list('Standard deviation', stdev);

   std_dev: procedure(a) returns(float);
     declare a(*) float, n fixed binary;
     n=hbound(a,1);
     begin;
       declare b(n) float, average float;
       declare i fixed binary;
       do i=1 to n;
         b(i)=a(i);
       end;
       average=sum(a)/n;
       put skip data(average);
       return( sqrt(sum(b**2)/n - average**2) );
     end;
   end std_dev;

 end;