In pursuance of maximum precision of error evaluation the approximation function and its parameters must minimize the root-mean-square deviation of the error values from the approximation function.
An expert method is the simplest way to estimate the approximation accuracy in accordance with the root-mean-square deviation of error values from the approximation function
by comparing it with the root-mean-square deviation of error values from mean errors [S.sub.PV] (Eq.
; [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII.] is a statistical estimate of root-mean-square deviation [sigma] ; E[xi], D[xi] = E[([xi] - E[xi]).sup.2] - respectively, average and dispersion of the random value.