All Questions
15 questions
100
votes
11
answers
280k
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
...
- 2,201
35
votes
3
answers
53k
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 ...
- 1,345
15
votes
1
answer
16k
views
Comparing mixed-effects and fixed-effects models (testing significance of random effects)
Given three variables, y and x, which are positive continuous, and z, which is categorical, ...
- 1,531
15
votes
1
answer
16k
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-...
- 451
8
votes
1
answer
8k
views
Different p-values for fixed effects in summary() of glmer() and likelihood ratio test comparison in R
I'm using glmer() with a binomial response variable. My optimal model has two fixed effects (flow and DNA) which in summary() show a non-significant p value but ...
- 135
11
votes
2
answers
6k
views
Comparing a mixed model (subject as random effect) to a simple linear model (subject as a fixed effect)
I am finishing up some analysis on a large set of data. I would like to take the linear model used in the first part of the work and re-fit it using an linear mixed model (LME). The LME would be very ...
- 183
9
votes
2
answers
4k
views
Obtaining p-values in a robustlmm mixed model via Satterthwaite-approximated DFs of the equivalent lme4 model?
I've used lme4 to fit a mixed model and could obtain p-values by using the lmerTest or afex packages. However due to heteroskedasticity (Levene Test) I also fit a robust model (rlmer command in the ...
- 383
7
votes
1
answer
7k
views
How can I obtain z-values instead of t-values in linear mixed-effect model (lmer vs glmer)?
I am wondering why in my lmer model the summary() only yields t-values rather than z-values, such as here:
...
- 505
7
votes
1
answer
5k
views
Big difference between a t-test and a F-test in a mixed model (anova vs summary in lmerTest)
While helping someone else with their analyses, I've run into a question regarding the difference between t-tests and F-tests for linear mixed models in lme4 for R, as provided by lmerTest. I'm aware ...
- 237
5
votes
2
answers
5k
views
I want to use pvals.fnc() to get p-values for a lmer() model but cannot get rid of correlations between random factors
My problem can be summarized very simply: I'm using a linear mixed-effects model and I am trying to get p-values using pvals.fnc(). The problem is that this ...
- 285
4
votes
2
answers
5k
views
Contrast for hypothesis test in R (lmer)
I'm running a lmer mixed effects model with a four-level factor (levels "0","10","100","1000") as the fixed effect.
lmer(free ~ reward.f + (1|S), longdata)
I ...
- 43
4
votes
0
answers
336
views
Testing Fixed and Random Effect of Mixed Model
This pdf illustrates nicely how is to test the random effect of multilevel model . But I am simulating data from a two-level model and estimating the parameters of the model for various combination of ...
- 771
2
votes
1
answer
1k
views
Mixed effect modelling with multiple, nested random variable
Goal: comparing pitch (Hz) on three types of words
Dependent variable: Hz
Fixed predictor variable: word-type, points (measurements taken from five points on each token, to capture Hz change within ...
- 33
2
votes
0
answers
2k
views
Satterthwaite degrees of freedom in lmerTest for a 3x2x2 mixed model vs. mixed ANOVA dfs
I have traditionally been running my analyses using aov and would like to switch to lmer. My questions is whether or not this is ...
- 613
1
vote
0
answers
289
views
Which of the (two) conflicting p-values should I use when estimating lmer using R
I've recently started using LMM which possibly gives me better insight into my DV. Only I got some contradictory data regarding whether some variable is significant or not.
The Us and Hed variables ...
- 31