All Questions
73 questions
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41
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How do I correctly formulate the random effects with repeated measures in a paired design
Sorry if this is a cross-posting, but I haven't found the exact solution for my problem yet.
Let us assume I have an experiment with 20 households, with 2 people each (1 female + 1 male).
Over the ...
- 33
0
votes
0
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31
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Mixed effect model for two levels of repeated measures
I have a repeated measures dataset that I am attempting to analyze using linear mixed effects regression. I would like to compare the effects of different products (A and B) on a dependent variable (y)...
- 11
1
vote
1
answer
84
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Describing data structure and specifying a linear mixed model in nlme with nested and crossed effects
I am trying to specify a linear mixed model to analyse data with the following structure and have several questions about correctly describing the structure of the data and how to specify the model. ...
- 65
1
vote
1
answer
30
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How to specify a model with multiple treatment groups, measured twice, repeatedly across a time period (lme4)?
I have 30 animals (factor: animal_id, 30 levels) which have been treated with a drug or a vehicle (factor: treatment, 2 levels). ...
3
votes
1
answer
57
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Linear Mixed Models: Accounting an effect as a random intercept or slope
My goal is to test whether reaction is significantly different between tasks (a, b, and c). However, the order in which I run the tasks in my experiment may affect the reaction. But I'm not interest ...
- 31
1
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2
answers
1k
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Random Intercept vs. Random Slope Linear Mixed Effects Model with Nested Data
I have read a lot about random intercepts vs. random slopes in linear mixed effects (LME) models, but I am confused on how to think about them when it comes to nested data. I have looked at other ...
- 41
1
vote
1
answer
240
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Simulation Study for a Nested Random Effect Model
I am trying to simulate data based on two random effects and no fixed effects.
The simulated data table contains nP projects and within each project ...
- 33
0
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0
answers
48
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Double nested lmer [duplicate]
On island biology I am currently doing a research on the difference in seed fall the between island.
For this research I collected plants on the islands and dropping 5 seeds for eacht plant.
This ...
- 23
2
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0
answers
68
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How to deal with the rank deficiency in lmer for nested variable
Data and background of the study:
The data is a repeat measurement of metabolite levels in responses to 2 types of stimuli.
The data measured in 4 sessions— ...
- 21
2
votes
1
answer
1k
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Grouped/Nested data in logistic regression
Update:
Added more meaningful example data
Setting:
In my study, each of three randomly chosen readers (A, B,...
- 120
0
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0
answers
57
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Mixed effects model specification lmer
I am quite new to mixed effects modelling but am starting to explore more complex designs for hypothesis testing using lmer in R. The model specification is ...
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0
answers
44
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lmer applicable for nested unbalanced experimentel design?
My experimental design causes me some headache. It consists of three sites (A, B, C). Each site contains two treatments (Treat1 and Treat2). Obtained data (resp1 and resp2) were recorded at eight ...
- 21
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0
answers
101
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Choosing between nested and crossed design
I'm looking to use a linear mixed effects model. Each participant will rate a given item using 9 scales, 1 of which is the outcome variable. There are 6 items in total. The aim is to determine which ...
- 93
5
votes
2
answers
520
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Glmer with count data, nested design and repeated measurements
Currently I try to fit a model for counted Individuals (response variable, integer numbers) in
Different types of traps (factorial explanatory variable).
I have two different Biotopes, and three ...
- 71
2
votes
1
answer
653
views
ANOVA represenation of mixed model with crossed random effects and uncorrelated variance structure
I was expecting this to be simple when I started, it seems to not be the case.
I am trying to model yield of bean genotypes. There were only 6 genotypes included. 3 trials were carried out in separate ...
- 155
1
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0
answers
28
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Hierarchical linear model in the context of an experiment
In an experimental study, I randomly assign participants to one of two conditions: Condition A (which they read Text A), and Condition B (in which they read Text B). After reading their assigned text, ...
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3
votes
1
answer
319
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Nesting random effect within fixed effect, with additional nested random effect. Nominal logistic
Very new to R so please pardon my naivety.
I am trying to run a sort of mixed effects nominal logistic regression model with my insect response data.
I have 2 rearing treatments (hot and cold) and 3 ...
1
vote
1
answer
183
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linear mixed effect models: random intercept, no fixed intercept interpretation
I'm learning about linear mixed effect models and I'm having a hard time interpreting a repeated measures model that has a random intercept, but no fixed intercept.
As an example:
...
- 337
1
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1
answer
99
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Does linear mixed effect models fit to analyse nested data?
I am searching for correlations between symptoms severity and the parameters of neural activity in a disease model. As predictors, I have two (slightly collinear) measures of disease severity on each ...
- 11
4
votes
1
answer
406
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Should repeated measures be included as a nested or a crossed random effect in glmer?
I have a field experiment looking at the effect of a seed-mix treatment on moth abundance and I am struggling to define the correct random effects structure. My experiment is structured like this:
I ...
- 41
3
votes
0
answers
46
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nested mixed effect ANOVA (lme4): can a factor be a fixed effect AND a nesting term for a random effect? [duplicate]
I study fish in a single large river and want to know if fish length differs between 3 large sampling 'sections' of the river. To answer this question, I measured hundreds of fish lengths within five ...
1
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0
answers
728
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Need help: nested fixed effects in nlme()
I have two fixed effects in a nonlinear mixed effect model. One is nested in the other, as the case here: "Specie" is nested in 'category'.
...
- 11
0
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1
answer
217
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Model specification in nlme: Random effects
My design has a total of 20 sites. 5 sites belong to each of four land covers: A, B, C and D. In each site, I have 5 sampling locations, 2 metres from each other. From each sampling location, I ...
4
votes
1
answer
60
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nesting/crossing in lme4
My question relates to the excellent answer given to this question a couple of years ago "Crossed vs nested random effects: how do they differ and how are they specified correctly in lme4?"
The answer ...
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0
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0
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204
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How to write model with fixed factors nested in random one?
I'm at the beginning of models understanding so this question is maybe childish, excuse me, please. It is close to this but there are some differences and I'm not sure how to implement that solution ...
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1
vote
1
answer
130
views
Mixed Effect Models - choice of the random intercept
I'm using the glmer function from lme4 package to model a binomial phenomena in a human DNA dataset. An allele can be missing (1) or not (0).
The dataset is created with 10 different samples. Each ...
- 31
3
votes
1
answer
53
views
Nesting in experimental desing
Suppose I have following results from my 2 experiments that contain 3 Block each and there are 4 treatments per Block (the example is R based)
...
- 121
1
vote
0
answers
48
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Mathematical description of covariance matrix
Using the nlme R package, I specified a model of the form
...
- 45
3
votes
2
answers
481
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Covariance structure with one or more random intercepts
I need to choose a suitable covariance structure including one or more random intercepts:
If one factor B is nested in another factor ...
- 45
2
votes
1
answer
465
views
2
votes
1
answer
850
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Mathematical notation / formula of a mixed effect model
I am unsure how to define the mathematical notation of a mixed model of R.
I built the model in this way:
...
- 23
1
vote
1
answer
636
views
Specifying random slope in a nested random effects
I collected crop yield and rainfall data from multiple counties and year ( > 30 years).
Each county can only belong to one province and each province can only belong to one region. I am interested in ...
- 991
0
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1
answer
246
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Linear Mixed Model in R: Rep. Measures, Nested, Random Effects
I ran a study with the following design: Subjects were presented 100 different stimuli and asked to indicate their liking (scaled from 0-10) for each stimulus. Each stimulus was part of only one of 4 ...
- 129
1
vote
1
answer
1k
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Multilevel nested glmer model (logistic regression) with 4 groups
I have 3 level nested data that is causing convergence problems (glmer function in lme4, R for multilevel logistic regression).
The Data
Country(4 groups) -> School(100 groups) -> respondent
A ...
1
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0
answers
61
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Multi-level modeling using lmer in R
I have nested data as followed: 'Learning group sessions' in 'students' in 'learning groups' (each learning group consisted of different students and the learning groups chose to have between 3 and 10 ...
- 21
1
vote
1
answer
1k
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Modeling repeated measures with a second layer of nesting using lmer
I am doing a longitudinal repeated measures study looking at the effect of age (maturation) on my test result (Y - a type of hearing test). My outcome Y, is numeric, and the main effect is age (age....
- 155
4
votes
0
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593
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notation for the regression equation in a nested and repeated measures random effects model
I'm looking for help with regard to the notation for a regression equation in a repeated measures model with nested data, $\eqref{eq:2}$, and connecting the notation back to my model specification, <...
- 439
3
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0
answers
2k
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LMER: specify interaction between main fixed effect and nested random effect
I have an experiment where I tested the influence of mycorrhizal fungi on plant growth, in six populations of a plant species. Each population had 10 maternal lines (families, Fam) in it. I'm ...
- 313
2
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0
answers
183
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GLMM Seedling Survivorship (binary outcome) - glmer & nested effects in R
I am attempting to fit a generalized linear mixed effects model in R using lme4, but am new to mixed models. I'd like to model Survivorship as the outcome of Treatment + Environmental Factors (...
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4
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1
answer
2k
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Repeated measures with nested data mixed effects model
Hi everyone: I'm hoping for help analyzing nested data in R.
I measured the mass of chicks at 3 time points; chicks were in one of two treatments (P and W) and in one of two environmental conditions (...
- 101
1
vote
0
answers
51
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Specifying mixed model for temperature measurements of termite mounds during the day in different soils
I've got a problem while trying to specify the 'right' nesting of the random effects of my dataset. The dataset registers hourly variations in temperature inside termite mounds:
Sampling was ...
0
votes
1
answer
3k
views
Mixed effects model with random and nested effects in lmer
I want to run a linear mixed effects model with nested and random effects using lmer in R, but continue getting errors. Two questions: what is causing the errors and how can I fix my model to run the ...
6
votes
1
answer
1k
views
Can a factor be regarded as both random and fixed effect?
I have a question about nested mixed effect model.
For example I have species A with different populations; these populations belong to two kinds of habitat types (with or without predators). So I ...
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2
votes
1
answer
1k
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Correlation structure of nested nonlinear mixed model
I would appreciate any help. I am trying to fit a nonlinear mixed model to some experiments. I have adopted a Gompertz function (y=Asym*exp(-b2*b3^x)), and the data used is 3 years of experiments (the ...
- 123
4
votes
1
answer
858
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Mixed Effects Model with nested data
I have (in my opinion) a nested data-set, which I want to analyze with a mixed effects model (R's lme4 function). I need help with the model specification. The data-set consists of three subject ...
1
vote
0
answers
474
views
Nesting fixed effects within random effect in lmer in R
I am a masters student in phonetics currently looking at voice onset time values (VOT) for voiced consonants in French.
I am intending to use a linear mixed effects regression to evaluate the effect ...
1
vote
0
answers
239
views
Fitting a nested experimental design in R
I am analyzing experimental growth data where I have fixed effects A and B (two levels each), an interaction between them (AxB) and 5 culture replicates for each combination of A and B. Numerical ...
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5
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1
answer
5k
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How to model nested fixed-factor with GLMM
I am a beginner on learning in GLMM and R, please forgive me if I am not making sense or asking something that is very basic.
I am trying to specify a nested fixed-factor in my GLMM model, but I don'...
- 53
1
vote
0
answers
561
views
Degrees of freedom for post-hoc comparisons in lmerTest
I have some experimental data in which treatments are nested within sessions which are nested within groups. It's tricky, because it seems like a simple between subjects comparison (TX1 vs TX2 vs TX3),...
- 11
5
votes
1
answer
2k
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Non-linear mixed model (nlme) with nested random effect, do not know how to include nested random effect when bootstrapping
I have fitted a nonlinear model with nested random effect, and I'm trying to estimate confidence intervals on predictions by nested bootstrapping, by following this explanation. I have edited my ...
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