Bertalanffy-Funktion und Ford-Walford-Formel

Abstract

Hohendorf (1966) has attempted to apply the relation between the parameters of the Ford-Walford-plot and the Bertalanffy-function, formulated by Taylor, to the somewhat difficult calculation of the parameters of the latter function. Working with values, calculated in this manner, demonstrated that they are not mathematically optimal. A careful analysis of the Ford-Walford-formula revealed, that it contains a third parameter which allows, in a simple manner, the derivation of the Bertalanffy-function. The relation between the parameters of the two functions is complicated by the fact that the regression line of the Ford-Walford-formula is adjusted to the minimum of the linear differences between observed and calculated values, while the optimal description of growth requires the minimum of the percentual deviations. © 1967 Biologischen Anstalt Helgoland.