Linked Questions

20 votes
2 answers
15k views

How to choose random- and fixed-effects structure in linear mixed models?

Consider the following data from a two-way within subjects design: ...
jokel's user avatar
  • 2,793
24 votes
2 answers
39k views

Repeated measures ANOVA with lme/lmer in R for two within-subject factors

I'm trying to use lme from the nlme package to replicate results from aov for repeated ...
mark999's user avatar
  • 3,298
28 votes
2 answers
5k views

Does it make sense for a fixed effect to be nested within a random one, or how to code repeated measures in R (aov and lmer)?

I have been looking through this overview of lm/lmer R formulas by @conjugateprior and got confused by the following entry: Now assume A is random, but B is fixed and B is nested within A. ...
amoeba's user avatar
  • 107k
22 votes
1 answer
626 views

Showing that 100 measurements for 5 subjects provide much less information than 5 measurements for 100 subjects

At a conference I overheard the following statement: 100 measurements for 5 subjects provide much less information than 5 measurements for 100 subjects. It's kind of obvious that this is true, but ...
DeltaIV's user avatar
  • 18.4k
11 votes
1 answer
5k views

How to perform a 4 by 4 mixed ANOVA with between- and within-subjects contrasts using R?

Beginner user of R here struggling with a repeated measures ANOVA. I have a dataset that consists of one between subjects factor with 4 levels (coded in a single variable called 'groups'), and one ...
aquadhere's user avatar
  • 113
11 votes
1 answer
4k views

Equivalence between a repeated measures anova model and a mixed model: lmer vs lme, and compound symmetry

I have some trouble obtaining equivalent results between an aov between-within repeated measures model and an lmer mixed model. ...
Tom Wenseleers's user avatar
6 votes
1 answer
1k views

Mixed ANOVA normality: which variables should be examined? (in universal and practical application with stats::aov)

I have spent a lot of time reading book chapters, articles, online tutorials, etc., but with no clear answer (mostly because they only describe one-way ANOVA or other very specific applications). ...
gaspar's user avatar
  • 234
1 vote
1 answer
1k views

Different results obtained with lmer() and aov() for three-way repeated-measures experiment

My question concerns results from one of my experiments, where analyzing the data with RM-ANOVA (using either ezANOVA or aov on ...
Julian Quandt's user avatar
2 votes
2 answers
275 views

Specify an lmer model for fully crossed data with replications

I have experiment data with multiple independent variables: shape - 2 factors color - 2 factors ...
sharoz's user avatar
  • 217
0 votes
2 answers
328 views

Mixed effects model: model fitting vs conceptual sense

I have a data from a 2 (load) x 2 (comp) x 2 (sal) full factorial repeated measures experiment and I'm trying to fit a linear mixed effects model to it. Here is a sample of the data: ...
Rooirokbokkie's user avatar
1 vote
1 answer
276 views

Testing zero variance component in a mixed model

I find this post relevant. The mock data-set is constructed the same way as in the post but with a different seed to produce zero variance in the mixed model. Think this as a three way anova, with A ...
Statisfun's user avatar
  • 777
3 votes
0 answers
363 views

3-way repeated measures ANOVA with nlme::lme assuming compound symmetry

For teaching purposes I want to show the similarity between a 3-way repeated measures ANOVA aov(y ~ A*B*C + Error(Subject/(A*B*C)), data) and the corresponding lmm ...
statmerkur's user avatar
  • 6,650
0 votes
0 answers
311 views

Repeated measures design and covariate using nlme & lme4

I conducted a full 3x2x2 (W1,W2,W3) within design with every participant experiencing the ...
Genscher's user avatar