Questions tagged [mixed-model]
Mixed (aka multilevel or hierarchical) models are linear models that include both fixed effects and random effects. They are used to model longitudinal or nested data.
2,877 questions with no upvoted or accepted answers
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Any Insights on the adoption and use of the Healthy Akaike Information Criterion (hAIC)?
Recently, I came across the Healthy Akaike Information Criterion (hAIC), introduced by Demidenko in his 2004 book "Mixed Models: Theory and Applications with R." Despite its (potential) ...
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When and why do I have to use "trait" for multinomial multilevel models with MCMCglmm in R?
I want to estimate a multilevel multinomial logit model but I am struggling with the terminology and notation used by the R-package MCMCglmm. There is documentation ...
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GAMM with multiple and crossed random effects
I am new to Generalized additive mixed models (GAMM) and I'm trying to model a behavioral response variable (time spent shading eggs by a nesting bird in minutes ...
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Adding a magnitude penalty to a GAM
This is a follow-up to a previous question of mine, explaining the problem in more detail in the hopes of getting more precise advice.
Consider the following structured additive regression model or ...
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Interpretation of glmmPQL() spatial autocorrelation output
I am modeling binominal data with random effects and spatial autocorrelation using MASS::glmmPQL().
Plotting the residual semivariogram of a model fit without ...
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How to simplify coxme survival models?
I have some questions about specifying a coxme (mixed-effects Cox proportional hazards) model in R and then simplifying it after reading the ...
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mixed effect model for method comparison of time series of paired measurements
A coworker and I are trying to analyze agreement between two measurement methods. I apologize in advance for needing some extra explanation due to the fact I'm an engineer whose statistics background ...
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Why does increasing number of observations in linear mixed model cause Bayesian modelling approach to fail?
I have a fairly good understanding of the theory behind Bayesian modeling and I have started to attempt some practical modeling using jags in R. I have been ...
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Mixed models formulation (GAMM, GLS, nlme): from R to mathematical notation
I have just finalised the analysis of a dataset fitting Generalised additive mixed models (GAMMs) with mgcv package in R v3.3.0. But I am having trouble in writing my models into their correct ...
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How should I include age in this mixed-effects model?
I've got repeated measures of hearing thresholds for a set of patients who each have a different inner ear measurement. This data is unbalanced, there are a varied number of measurements at varied ...
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T tests on proportions - Wrong, but how wrong?
Background: In psychology, and probably a number of other disciplines, it's common practice to test between-groups effects on a binary variable, such as accuracy, by aggregating data within ...
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Degrees of Freedom using "Containment" method
I have a question about the way SAS uses the "containment" method to obtain degrees of freedom in mixed models. In particular, I think SAS does the wrong thing in obtaining df for least-squares means (...
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R model.matrix and makeContrast. Understanding model and possible contrast
I have measurements from 12 mice, grouped in two conditions. I each mouse I have measurements from 4 tissues. The design is not balanced, 5 mice in condition1 and 7 in condition2.
After reading the ...
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Effect size measure for doubly-repeated measures design?
Update:
I haven't gotten any answers, so I am simplifying my question. Say I measure test scores of $100$ people in one of two conditions. Each test has $10$ items. On each item, each person can ...
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