Linked Questions

53
votes
9answers
113k views

How to obtain the p-value (check significance) of an effect in a lme4 mixed model?

I use lme4 in R to fit the mixed model lmer(value~status+(1|experiment))) where value is continuous, status and experiment are factors, and I get ...
26
votes
3answers
37k views

How to get an “overall” p-value and effect size for a categorical factor in a mixed model (lme4)?

I would like to get a p-value and an effect size of an independent categorical variable (with several levels) -- that is "overall" and not for each level separately, as is the normal output from ...
12
votes
1answer
6k views

Confusion over lmer and p-values: how do p-values from memisc package compare to the MCMC ones?

I was under the impression that the function lmer() in the lme4 package didn't produce p-values (see ...
9
votes
2answers
8k views

P value for interaction term in mixed effects models using lme4

I'm analysing some behavioural data using lme4 in R, mostly following Bodo Winter's excellent tutorials, but I don't understand ...
6
votes
1answer
3k views

Conflicting results of summary() and anova() for a mixed model with interactions in lmer+lmerTest

I recently came across what I think may be a problem in how the anova() function from the lmerTest packages computes its F-...
0
votes
3answers
3k views

Mixed-effect model in R using lme for data count data with two fixed effects and repeated measures

I have no idea how to analyze this dataset. I am asking if two genotypes, T and M, respond differently to a treatment, E2 (I also have a control, CON). All 36 animals were given both E2 and CON in a ...
2
votes
1answer
3k views

R lmerTest step() function returns significant random effect without equivalent significant fixed effect

I do have a 2 level data set with 3 observations nested in one person. I am fitting a mixed model including 71 predictors and 28 random slopes in the following manner: ...
3
votes
1answer
416 views

Hypothesis testing: If not a p-value in mixed effect models, then what?

I've been working on a messy, repeated measures data set of endocrine data looking at a small group of variables (after eliminating several uninteresting contenders in exploratory data analysis), each ...
1
vote
1answer
132 views

lmer model doesn't return t-value [closed]

I'm currently running a time series analysis which requires me to fit lmer models to each of my data points. Here is my code : ...
2
votes
3answers
83 views

Why do main effects lose significance when I include interactions?

I have an experiment with 8 binary IV, 1 three-level IV (all categorical) and a continuous DV. I run an lmer with all main effects of all variables like so: ...