Weibull

The Weibull growth model is described by the equation:

where l = length, (or weight, height, size) and t = time.

The four parameters are:

β, is the lower asymptote;
L∞, is the upper asymptote;
k, is the growth rate and

δ, is a parameter that controls the x-ordinate for the point of inflection.

The point of inflection on the x axis lies at:

If δ = 1 the Weibull is a simple exponential growth curve.

The following graphs show example plots of the Weibull growth curve for different values of δ (delta).