Generalised logistic curve

The generalised logistic (or Richard's) curve is a widely used and flexible function for growth modelling.

<math>Y = A + { C \over (1 + T e^{-B (x - M)}) ^ {1 / T} }</math>

where Y=weight, height, size etc; X = time.

It has five parameters:

A

the lower asymptote;

C

the upper asymptote;

M

the time of maximum growth;

B

the growth rate;

T

near which asymptote maximum growth occurs.