/* Runs test(Greater than 0.5 or not) for U(0,1) sequence */
new; cls;
x=rndu(100,1);
call halfrunstest(x);



proc halfrunstest(x);
   local n,y,nA,nB,R,ER,varR,i,Z,pval;
   if ismiss(x);
      errorlog "Warning: missing data found.";
      x=packr(x);
   endif;
   if not(x>=0 and x<=1);
      errorlog "Error: This is not U(0,1).";
      retp(".");
   endif;
   n=rows(x);
   y=(x.>0.5);
   nA=sumc(y);
   nB=n-nA;
   R=1;
   i=2;
   do while i<=n;
      if y[i-1]/=y[i];
         R=R+1;
      endif;
      i=i+1;
   endo;
   ER=2*nA*nB/(nA+nB)+1;
   varR=2*nA*nB*(2*nA*nB-nA-nB)/((nA+nB)^2*(nA+nB-1));
   Z=(R-ER)/sqrt(varR);
   pval=2*(1-cdfn(abs(Z)));
/* results */
   print "Runs Test(x>0.5 or not):";
   print/rz "n   =" n;
   print/rz "nA  =" nA;
   print/rz "nB  =" nB;
   print/rz "R   =" R;
   print    "Z   =" Z;
   print    "pval=" pval;
   if nA<20 or nB<20;
      print "(Waring: P-value above is not the case. See Table instead.)";
   endif;
   retp(Z);
endp;