NAMELIST      ; X = ... $

                     INCLUDE       ; New ; zi <= lower & zi # -999 $

                     CALC          ; DF1 = N - col(X) ;

                                   ; lowss  =  ess(X,y) / DF1 $

                     INCLUDE       ; new ; zi >= upper & zi # -999 $

                     CALC          ; DF2 = N - col(X)

                                   ; highss =  ess(X,y) / DF2 $

                     CALC          ; F = highss / lowss ; FTB(.95,df1,df2) $