FITTING GENERALISED LOGISTIC IN GENSTAT

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Models are fitted with these two instructions 
MODEL weight; RESIDUALS=res; FITTED=fit 
FITCURVE [CURVE=glog] age

The MODEL statement specifies the response variable.

The FITCURVE statement specifies the curve to fit and the independent (time) variable.

The option CURVE=glog specifies that we want to fit the generalised logistic curve. Other options could be

If you would like to explore various models you can obtain the data and the Genstat code used above.

A further example is available which illustrates the fitting of separate growth curves for each experimental unit. The coefficients are averaged for the various combinations of treatment factors in order to identify possible effects of treatments on the shape of the curves.

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Growth curve modelling 1.6.95 Page : 12a of 12