data boards; infile "D:\stat505data\boardstiffness.dat"; input x1 x2 x3 x4; run; proc princomp std out=pcresult; var x1 x2 x3 x4; run; data mahal; set pcresult; dist2=uss(of prin1-prin4); run; proc print; var dist2; run; proc sort; by dist2; run; data plotdata; set mahal; prb=(_n_ -.5)/30; chiquant=cinv(prb,4); run; proc gplot; plot dist2*chiquant; run;