Posts Tagged ‘ lme4 ’

Surviving a binomial mixed model

November 11, 2011
By
Surviving a binomial mixed model

A few years ago we had this really cool idea: we had to establish a trial to understand wood quality in context. Sort of following the saying “we don’t know who discovered water, but we are sure that it wasn’t … Continue reading →

Read more »

Covariance structures

October 26, 2011
By
Covariance structures

In most mixed linear model packages (e.g. asreml, lme4, nlme, etc) one needs to specify only the model equation (the bit that looks like y ~ factors...) when fitting simple models. We explicitly say nothing about the covariances that complete … Continue reading →

Read more »

Large applications of linear mixed models

October 18, 2011
By
Large applications of linear mixed models

In a previous post I summarily described our options for (generalized to varying degrees) linear mixed models from a frequentist point of view: nlme, lme4 and ASReml-R†, followed by a quick example for a split-plot experiment. But who is really … Continue reading →

Read more »

Linear mixed models in R

October 16, 2011
By

A substantial part of my job has little to do with statistics; nevertheless, a large proportion of the statistical side of things relates to applications of linear mixed models. The bulk of my use of mixed models relates to the … Continue reading →

Read more »

GLMM Hell

July 7, 2011
By
GLMM Hell

I have been starting to analyze some data I have of repeated counts of salamanders from 5 plots over 4 years. I am trying to develop a predictive model of salamander nighttime surface activity as a function of weather variables. The repeated counting l...

Read more »

Multiple Comparisons for GLMMs using glmer() & glht()

June 14, 2011
By
Multiple Comparisons for GLMMs using glmer() & glht()

...that's an example of how to apply multiple comparisons to a generalised linear mixed model using the function glmer from package lme4 & glht() from package multcomp. By the way you see a nice example for visualizing data from a nested sampli...

Read more »

lme4 stands 4 Linear mixed-effects…

February 19, 2010
By
lme4 stands 4 Linear mixed-effects…

There is a certain hype about mixed (and random) effects among statistician and analysts. You can show some love to Douglas Bates and Martin Maechler for maintaing the lme4 package for our cupid, R I copy the entity of the information of the projects page. Doxygen documentation of the underlying C functions is here. The

Read more »

useR! 2009 acceptance: presenting influence.ME

April 23, 2009
By

The organizing committee of the useR! 2009 conference just informed me, that my submission for presenting my extension package influence.ME, has been accepted! Influence.ME is a new R package that I’m currently developing, with the indispensable ...

Read more »

R-Sessions 32: Forward.lmer: Basic stepwise function for mixed effects in R

February 13, 2009
By

Intended to be a customized solution, it may have grown to be a little more. forward.lmer is an early installment of a full stepwise function for mixed effects regression models in R-Project. I may put in some work to extend it, or I may not. Neverthel...

Read more »

R-Sessions 31: Combining lmer output in a single table (UPDATED)

February 5, 2009
By

There are various ways of getting your output from R to your publication draft. Most of them are highly efficient, but unfortunately I couldn’t find a function that combines the output from several (lmer) models and presents it in a single table....

Read more »