FERRORS /
        PERCNT(pp)

        NONE      
        OWN       
        STATISTIC 
        THEORY    

Purpose

  Specify errors of experimental data to be fitted.

PERCNT(pp)
   Each data point has an y-error of pp percent of the y-value

   No errors are known

   Take errors associated with data points itself.

   Assume statistical errors computed as square root of y-values

   Errors are derived from the fit function as square root of the
   computed function y-values.