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On page 146 of Pinheiro & Bates, they mention models where every fixed effect has an associated random effect. What does it mean for a fixed effect to have an associated random effect? Thanks for any clarification, Scott Rifkin

How can I set the plot range for a boxplot using the boxplot() function? For example, the values in the boxplot go from -3 to 3 (outliers plotted), but I'd like the y axis to go from -5 to...

Why does: > numeric(0.2*25) return [1] 0 0 0 0 0 but > numeric((1-0.8)*25) returns [1] 0 0 0 0 [running version 3.2.0] [Apologies if this has been asked before - it's a...

The goal: simulate chi square mixture distributions as a way of simulating likelihood ratio test statistics for some mixed models where the more specific model has some zero variance components (a la Pinheiro and Bates pg. 84-87) The problem...

I'm trying to set up a mixed model to solve using lme. It will have 3 fixed effects, two random effects and two interaction terms. I've been reading Pinheiro's and Bates's book on the nmle library...

I have an experiment with an interaction (VT) between Varieties and Time. There are 12 Varieties and 2 Times (Early and Late), and Time is a fixed affect. I have been estimating a single variance from this interaction using pdIdent...

David, Thanks for your reply and suggestions of packages - let me clarify what I am looking for: The web editor you pointed out is the sort of equation editor I'm looking for and I had seen others like this...

I'm looking for a package that would take a mathematical function written in symbolic notation and convert it into R code. What I have in mind would be something like the following: 1) Have a GUI (e.g. something...

This is an update to my previous post today after finding some previous posts about crossed random effects. Any comments would be much appreciated. I have two random factors (Plot and Variety), one fixed factor (Time). I got rid of...

Ista, On the one hand I'd like it to be as flexible as possible so the students could really come up with whatever they like. On the other hand, restricting their choices probably would make it easier to do...

I have the following dataset: 96 plots 12 varieties 2 time points The experiment is arranged as follows: A single plot has two varieties tested on it. With respect to time points, plots come in 3 kinds: (1) varietyA, timepoint...

1) I have the following data situation: 96 plots 12 varieties 2 time points 2 technical treatments the experiment is arranged as follows: a single plot has two varieties tested on it. if variety A on plot #1 has treatment...

I'm trying to fit a nested mixed model using lmer and have some questions about the output and my model formulations. I have replicate measures on Lines which are strictly nested within Populations. (a) So if I want to...