All Questions
22 questions
0
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1
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19
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How can I get the population variance from a mixed model?
I supposed it is a basic question, but I'm stuckle on it and I can't find the solution.
I have a date base with the slurry dry matter content from different pig production stages (CATEGORY), also, ...
- 33
0
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0
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29
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Why does the ICC differ when comparing multilevel models with using log transformations of the outcome variable in R using lme4?
I'm currently working on a multilevel modeling project in R utilizing the lme4 package. The primary aim of the research is to assess the relative importance of between-family and within-family ...
- 41
4
votes
1
answer
64
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Calculating variance of a dependent variable with multiple fixed effects
I am kind of a stats noob but I figure someone here may have some insight. I am running a linear mixed effects model in R, reminiscent of what's below:
...
- 121
1
vote
1
answer
85
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Do I need a nested random effect if I do not care about decomposing variance within clusters?
Consider I have a linear mixed effect model fitted via the R package lme4 with a nested random effect structure as:
model<-lmer(y~x+(1|A/B/C))
If I look at the ...
- 89
1
vote
1
answer
178
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Estimation of random intercept and random slope for singleton cluster in multilevel modeling
I am performing some multilevel analyses with the R package lme4.
The study design is longitudinal with the hierachical structure of observations (L1) nested into study participants (L2). I have 215 ...
0
votes
2
answers
310
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Anova and mixed effect models (lm4 / nlme) return complete different effects
As a continuation of a previous topic, I would like to address a similar experience.
Subjects completed an experiment in which their electrodermal activity was recorded. For each subject there are 72 ...
AlexKas
0
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0
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26
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Linear mixed models unequeal group variances and model fit
I have data from two groups (divisions) of participants that consider attention lapses. The question is, first, do the number of attention lapses change over the two testings, and second, do the ...
- 77
2
votes
1
answer
3k
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How to get the proportion variance explained by each predictor in an lmer() model?
Is there a way to get the proportion of variance explained by individual fixed effects in a mixed effects model?
I thought that the partR2 package could do this, ...
- 2,701
1
vote
0
answers
85
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Is regression towards the mean happening when we use a control group?
I have a subset of 40000 participants in my study. From those I would like to study those with higher weight longitudinally, and compare them with those with healthy weight.
I observe, that those with ...
- 270
2
votes
2
answers
248
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How to estimate proportions of variance in outcome variable attributable to each individual fixed effect variable in lmer?
I am using multivariate models in lme4 to try to work out, quantify and compare the effects on a single outcome variable of a large group of fixed effects variables. Because the data are at week and ...
- 213
7
votes
2
answers
395
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Don't understand why glmm random effect variance is zero. Have reviewed similar questions still dont get it
I study a colonially-nesting bird species. I am trying to perform an AICc evaluation of GLMMs for a nest site selection study. I collected data at nest sites and paired random sites. I want to ...
- 83
2
votes
0
answers
162
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How to estimate variance for identical & fraternal twins with a mixed model
I am using the twins data from OpenMx and am curious to estimate the empirical covariance structure for BMI differences in monozygous and dizygous twins:
...
- 64.8k
3
votes
1
answer
189
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How to compute correlation of random slopes for X between two Conditions with (X*Condition|subject) model in lme4?
We have the following model:
Y ~ X*Condition + (X*Condition|subject)
Y = dichotomous variable; values 0,1
X = continous variable; values ca. 0-3000
Condition ...
- 1,782
2
votes
1
answer
2k
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Partitioning variance within a level in a 3-level mixed effects model
I have a 3-level repeated measures model setup observations (level-1) nested within patients (level-2) nested within providers (level-3). One of my questions is the percentage of variance explained at ...
- 163
2
votes
0
answers
295
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Using lme4 and glmer (logit) to estimate variances of random intercepts
Our data set consists of a matrix with a few thousand respondents (rows), many items of ten surveys (columns), and all 0’s and 1’s for a certain survey answering behaviour (either responding ‘I don’t ...
- 21
3
votes
1
answer
1k
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Understanding variance components with an interaction structure
Suppose that I have the following dataset in R:
library(lme4)
data(Machines,package='nlme')
mydata <- Machines[Machines$Machine!='C',]
There are 3 levels with ...
- 2,769
10
votes
2
answers
7k
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How can I test for differences in variation between groups in a mixed model (lme4)?
I would like to test for differences in variation, not in means, between two sites. By looking at a boxplot of my data I see that bird song in one site look much more variable in length than in ...
- 101
1
vote
0
answers
288
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Specify variance structure TOEP(1) in lmer for mixed model
How can I do the following job in R? More specific: how can I define type=toep(1) in R?
...
- 11
18
votes
4
answers
28k
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Interpreting random effect variance in glmer
I'm revising a paper on pollination, where the data are binomially distributed (fruit matures or does not). So I used glmer with one random effect (individual plant)...
- 313
2
votes
0
answers
452
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Multiple comparisons for variance structure in R lme fit
How can I compare variances for different levels of a factor in a mixed effect model?
I'm fitting a mixed effects model (in R using the ...
- 121
7
votes
1
answer
8k
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Residual variance for glmer
I am running a glmer model and I want to determine the total variance. My data is for survival and it is coded as 0 and 1, where 1 represents that the individual survived and 0 represents that the ...
- 71
16
votes
1
answer
21k
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How to estimate variance components with lmer for models with random effects and compare them with lme results
I performed an experiment where I raised different families coming from two different source populations. Each family was assigned one of two treatments. After the experiment I measured several traits ...
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