A logistic growth curve model with random effects;
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Model descriptionA growth curve model was fitted to the "orange tree" data by Pinheiro & Bates (2000, Ch.8.2) as an illustration of the R (S-Plus) routine nlme. The logistic growth curve is given asy = f1
/(1 + exp[-(t-f2)/f3])
] + e,
where y is the response and t is the age of the three. The regression parameters to be estimated are: f1, f2 and f3, and e is the residual error term. A random effect u is added to the parameter f1. A full description of the model can be found here: orange.pdf. Comparison with nlmeParameter estimates are shown in the following table.
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