search for: pinherio

...treatment 12TFYM etc), which are replicated in 3 blocks. For the magnesium soil data, I have created the following groupedData object: magnesium<-groupedData(Mg~year|treatment, inner=~block) Where mg=magnesium Kg/ha As it is a repeated measures I was going to use an lme. I have looked at Pinherio and Bates : Mixed-Effects models in S and S-plus and I am getting slightly confused. In order to fit the lme, should I specify the data to use in the model as the grouped structure model? If so is the following command correct: Model1<-lme(mg~treatment, random=block|year, data=magnesium)? I...

Hola a tod en s, estoy trabajando con modelos de regresión mixta con el paquete "nlme", concretamente con la función "lme". Una vez que hago mi modelo y el summary del mismo obtengo por ejemplo la significación (valor p) de la variable independiente, así como el valor del AIC para comparar mi modelo con otro similar, pero no sé cómo obtener un valor del grado de ajuste de la

...hat say the random effect for the intercept has a different variance per treatment group? Thus, in the model equation, we'd have say b_ij represent the random effect for patient j in treatment group i, with variance depending on i, i.e, var(b_ij) = tau_i. Didn't see this in the docs or Pinherio & Bates (section 5.2 is specific for modelling within group errors). Sample repeated measures code below is for a single random effect variance, where the random effect corresponds to patient. cheers, dave z <- rnorm(24, mean=0, sd=1) time <- factor(paste("Time-", rep(1:6...

I have a fisheries Ricker stock-recruitment non-linear model which I am trying to code up in R (after failing in MATLAB). There are two fixed parameters and a random environmental effect that is linked to a first order lagged correlation fixed parameter. Are there any examples of fitting this model I could follow? Cheers Norm Good Fisheries Biologist (Mathematician) Southern Fisheries Centre