All Questions
Tagged with lme4-nlme repeated-measures
377 questions
3
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1
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327
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Repeated measures regression or time series analysis?
I have managed to confuse myself again, so I hope you could give me some tips or point into the right direction.
I have pesticide residue data in different plant matrices (e.g. flowers, leaves) from ...
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11
votes
1
answer
2k
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Minimum number of repeated measures and levels per nested random effect
I often read the guideline that a random factor should at least have 5-6 levels. However, it is not yet really clear to me if there is (i) a minimum number of levels for a nested factor within a block ...
CommunityBot
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2
votes
0
answers
112
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Which random effects should be included in my mixed-effect model? Repeated measures design with 3 within-subject factors
I am considering a design where the dependent variable ('DV') is measured in each subject ('Sub') for each level of three factors ('TH', 'A', and 'B'). From what I understand this is a repeated ...
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 ...
- 82.8k
2
votes
1
answer
121
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Repeated measures mixed model in r
I want to compare how fast children from 2 countries [Country] run on a treadmill [Speed] at two time points [Time]. Specifically, I wanto to see whether the change over time is different in those two ...
- 13.3k
2
votes
1
answer
424
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How to conduct a two-way repeated measures ANOVA in R
I'm sorry if this question has been clarified in another post. I've looked around for some time and have been unable to find an answer.
I'm conducting research to evaluate heart function before and ...
- 20.9k
4
votes
1
answer
826
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A correct mixed model for longitudinal data
This is a rather basic question and there are many similar questions here on CV. However, I could not find answers to my specific three questions below. My apologies, if I may have overseen something.
...
- 65.9k
3
votes
1
answer
82
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nesting vs not nesting?
I am following the tutorial from Bodo Winter.
Bodo created the following model on page 10:
...
- 65.9k
1
vote
0
answers
215
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Linear mixed model for analysis between 2 methods and intra inter observer reliability/agreement
i have ultrasound data measuring strain of myocardium as the dependant variable. Now i want to compare reliability and agreement of the measurement system between the 2 methods, the test retest and ...
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1
vote
0
answers
56
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How to model and plot a distribution of choice frequency (categorical variable) split by 2 levels of within-subject
I measured the difference in people's habits between this time last year and now. Specifically, I want to explore the difference in group size when people go to camping: do people tend to go with ...
- 207
2
votes
1
answer
391
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Mixed model dfbetas procedure question
I have two questions that I will explain in detail and give an example:
When iteratively calculating dfbetas in a linear-mixed model and creating a fixed-effect dummy variable to remove the influence ...
- 65.9k
1
vote
0
answers
42
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multilevel model specification
We had participants complete a virtual maze. We showed the participants the correct path through the maze, then had them complete the maze 10 times. The maze consisted of 15 decision points, which are ...
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1
vote
1
answer
134
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Why significant predictors are different for two highly correlated dependent variables?
I am using linear mixed-effects (LME) models to investigate the longitudinal effects of maternal factors on infant adiposity indices. Infant adiposity was measured at 3-time points (birth, 3 months ...
- 102k
4
votes
1
answer
461
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Why does this error occur with my linear mixed models?
I am attempting to run linear mixed effects models using the function lmer() in order to analyse the effect of the direction of change (single categorical fixed effect) in weather parameters over a ...
- 65.9k
4
votes
1
answer
295
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Nested and crossed effects in 3-way interaction in lmer
I am running a mixed model in lmer, testing the effects of Covid restrictions on sleep, comparing 2 cohorts of individuals- one from 2019 and one from 2020, coded 0/1 (between subjects). Each ...
- 31.2k
1
vote
0
answers
105
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Linear mixed model with many NAs
I am running a linear mixed effects model in R using the lmer4 package. I was wondering if my data is structured in the right way for this purpose. In a few words I have a response variable "...
4
votes
1
answer
47
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Mixed Effects Nesting
I have a simple model with mixed effects. I asked subjects ten questions, five easy and five hard, and saw how much they relied on advice, based on who their advisor was (algorithm or peer) and how ...
- 65.9k
2
votes
1
answer
769
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Very different results with ezANOVA and LMER in R
I have a repeated-measures design, so I use ezANOVA. However, I was interested in a numeric (ordinal) predictor, so I ran two models: with ezANOVA (ez package) and lmer (lme4 + lmerTest). The results ...
3
votes
1
answer
630
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Causal inference from mixed-effects modelling on non-experimental repeated-measures data?
This is a more conceptual question and I think it highlights my lack of knowledge of what can be assumed using mixed-effects modelling on a non-experimental repeated-measures data.
Let's pretend we ...
- 65.9k
2
votes
1
answer
113
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New to lme4 in R - am I modeling this correctly?
Experiment: Given mice of two genetic backgrounds (normal, mutant), is there a difference in brain inflammation as determined by fluorescence intensity of an inflammatory marker?
Data: 19 mice (12 in ...
- 65.9k
3
votes
2
answers
192
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How to model this mixed model
I have following data:
Each column represents a specific manufacturer (that's why I skipped the title) and from each one I have several sensors. Now I would like to perform a mixed model. I thought ...
- 65.9k
5
votes
1
answer
914
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Between- and within-person level effects when using multilevel modelling for longitudinal data in R
I’m using nlme package in R for analysing longitudinal data. The aim is to understand if changes in need satisfaction (TNS) and ...
- 65.9k
5
votes
1
answer
2k
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p-value random effect in glmer() in lme4 package
I know that in order to test whether a random effect has a significant impact on a model it's necessary to sequentially remove one random effect at a time and check each model pair with ...
- 65.9k
3
votes
1
answer
976
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Random effects not appearing for some levels in lmer model - Why would that be?
Here's my code in R but I unfortunately can't share my data, and I can't reproduce it by randomly creating a data set.
I can say that the data set has 1,561 cases....
- 65.9k
4
votes
1
answer
123
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Question about the structures and conditions of validity of the mixed-effect model
In class we are told to be very careful when using mixed models and to use the simplest models, to avoid talking nonsense. I posted questions previously about this but I will come back to the wording ...
- 65.9k
4
votes
1
answer
124
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Is my design nested or crossed? Question concerning specifying random effects with lmer in R
I've run an experiment where 120 participants (PP) viewed 40 quotes (Item) each (presented in Facebook format) and were asked to ...
- 65.9k
7
votes
1
answer
421
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Mixed Effects Model
Sorry for asking my question even though I know there are some subjects about mixed effect model on the forum. But I think my question is somewhat different.
I have to answer to a question about ...
- 65.9k
9
votes
1
answer
1k
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Reading multilevel model syntax in intuitive ways in R (lme4)
Below, I have 3 lme4 longitudinal mixed-models. Throughout, y is the response variable, group...
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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 ...
- 65.9k
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 ...
- 65.9k
10
votes
1
answer
10k
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Estimating correlation between random slopes and random intercepts using the lme4 package in R
For answering my research question I am interested in the correlation between the random slopes and random intercepts in a multilevel model, estimated using the R library lme4.
The data I have is: Y ...
- 65.9k
3
votes
1
answer
583
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Nested random factor with confounding (random?) variable
I have a question on how to specify a GLMM. I made an experiment with two treatments (control and treated) to test the effect of a water contaminant on reproductive cells of tadpoles. I have data on ...
- 65.9k
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 ...
- 65.9k
4
votes
1
answer
238
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Can I use different data types in a general linear mixed effects model?
I've become quite familiar with linear mixed effects models but I'm not very certain about their General counterparts.
I have a data set which looks like the following:
...
- 65.9k
4
votes
1
answer
8k
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How to include nested fixed effects with different levels across conditions in lmer?
My design is as follows:
one dependent variable (brain activity),
a "condition" factor I manipulated with two levels (c1 and c2)
a "region of interest" factor with two levels (r1 ...
- 65.9k
2
votes
1
answer
2k
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Test significance of categorical variable with multiple levels, when model also includes interactions
I am fitting a mixed model with the command
model=lmer(Activity ~ 1 + Novelty*Valence*ROI + (1 | Subject))
Activity is a measure of brain activity, Novelty and ...
- 65.9k
3
votes
1
answer
455
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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 :
...
- 65.9k
4
votes
2
answers
1k
views
Difference between lm, PROC GLIMMIX and glmer
I wanted to analyze my data below to see the effect of treatments (CC,CCS, CS and ...
- 65.9k
1
vote
1
answer
1k
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Which family to use for GLMM with 3-level categorical response variable in R?
I'm building a model with a 3-level categorical response variable and both fixed and random effects to analyze data from a survey of volunteers. My response variable ('wellbeing', self-reported) has ...
- 65.9k
2
votes
1
answer
9k
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Scaling predictors in mixed models
I collected data over multiple locations and years on crop yield and want to regress yield as a function of rainfall and heat-stress which are in two different units. Suppose my dataframe has 5 ...
- 65.9k
6
votes
1
answer
401
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Proper syntax for coding group level variables in mixed effect model using GLMER
I am running a multilevel log odds regression on a dataset that is at the individual level. Each individual belongs to a district, and there are both individual level variables (which vary by ...
- 65.9k
2
votes
1
answer
154
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Why are my random effects not identified, even when I have repeated measures [closed]
I want to evaluate the effect of number of flowers (fixed effect) and soil nutritional content (fixed effect) on size of flower. The experimental design consists in 16 plants growing on two substrates ...
- 65.9k
2
votes
2
answers
815
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GLMM - binomial
I am rather new to R. I am trying to run a GLMM - binomial logit.
I have three independent variables (x1, x2, x3) and a dependent variable (...
- 65.9k
3
votes
1
answer
1k
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Can I use location as a random effect when treatment levels are not exactly the same across those locations?
I am working on a data set that aims to test various treatments with respect to vegetation regeneration. The experiment is replicated at many sites across a large geographical gradient and has been ...
- 65.9k
1
vote
1
answer
222
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Different results in a mixed model when compared with raw data
I ran a model with reaction time as my DV and PWI Condition (2 levels) as one of the fixed factors.
I used contr.sum for all fixed factors. I ran the following model to look for differences in ...
- 65.9k
2
votes
1
answer
47
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Minimum no. of grouping variables in mixed models
I have data where I collected y and predictors x1, x2, x3...
- 65.9k
10
votes
2
answers
16k
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1
vote
1
answer
1k
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model for non-linear data with repeated measurements
I have to do a model for non-linear data with repeated measurements.
I worked with predatory insects.
I did an experiment with 4 treatments, where per each treatment predators received a different ...
- 65.9k
1
vote
2
answers
2k
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Notation for three-level repeated measures random intercept model (lme4 model included)
I am trying to wrap my head around the notation for this three-level model.
Level 1: Repeated observations
Level 2: Client
Level 3: Therapist
I am using a baseline intercept model to calculate ...
- 65.9k
14
votes
1
answer
2k
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Repeated measures analysis: why nest experimental factors within subject factor?
Consider a pure repeated measures design, with (let's say) 3 experimental within-subject factors A, B, and C, and (for simplicity) 2 levels per factor. So we have 2*2*2 = 8 measurements per subject.
...
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