A logistic growth curve model with random effects;



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 (SPlus) routine nlme. The logistic growth curve is given asy = f_{1}
/(1 + exp[(tf_{2})/f_{3}])
] + e,
where y is the response and t is the age of the three. The regression parameters to be estimated are: f_{1}, f_{2} and f_{3}, and e is the residual error term. A random effect u is added to the parameter f_{1}. A full description of the model can be found here: orange.pdf. Comparison with nlmeParameter estimates are shown in the following table.
