All Questions
8,501 questions
0
votes
1
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35
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Using a mixed effects model to understand the population?
I have this repeated measures data in R (simulated) that represents multiple regions in the same country (i.e. multiple measurements over time for each region - assume regions are measured at the same ...
- 667
0
votes
0
answers
20
views
Simulating Multilevel Data to Achieve a Specific Marginal R-squared Value
I am working on simulating multilevel data with the goal of achieving a particular marginal R-squared value through simulation. Given that variance decomposition in multilevel modeling can become ...
- 153
0
votes
0
answers
5
views
Regression table for fixest and plm models?
I am working with fixest and plm models. I usally use fixest's etable for fixest objects and stargazer for plm. The problem is ...
- 183
1
vote
0
answers
38
views
How to estimate population variance from a mixed model with a categorical variable?
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, ...
- 41
1
vote
2
answers
30
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Should I conduct a multilevel for this or another analysis? Need help
I have three sources of data (teachers, parents and students) assessing students, in three waves. I want to assess all and see the differences between moments but then I also want to use variables for ...
0
votes
1
answer
25
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Appropriateness of treating study site as a random effect in mixed-effects models when each site has a single predictor value
I have data from 12 study sites, each with a corresponding value for the area of built-up surface. At each site, I measured the body size of turtles and am interested in examining how body size varies ...
1
vote
1
answer
90
views
+50
Interpretation of estimated effect of a predictor variable when it does not vary within a sampling unit
Let us consider the following scenario. John is soon going to quiz his students and he is interested to know if the font type with which a quiz is formatted is associated with the performance of the ...
2
votes
0
answers
17
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Convergence of Latent Class Linear Mixed Model with LCMM in R with multiple outcome variables
I am seeking help getting my latent class linear mixed models to converge using the LCMM package in R.
I’m working with a large longitudinal dataset on cognitive functioning in Parkinson’s disease, ...
- 21
-1
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0
answers
8
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what happens when a network has low closeness centrality - what happens to nodes on the periphery [closed]
I have thirty-nine nodes with closeness centrality scores but I do not know what to say about the nodes on the periphery who do not have scores.
3
votes
1
answer
46
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Calculate marginal effects for random effects model with two crossed random effects
I am trying to get effects marginal of two crossed random effects (using STAN or brms). I understand how to do it for a single random effect following McElreath's book and Kurtz's brms version of the ...
0
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0
answers
15
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Mancova or other method for this design of experiment challenge?
I'm working on a factorial experiment to optimize removal efficiency (Y) with two factors: velocity (A, 2 levels) and dose (B, 3 levels). I'm also considering water quality (M) as a covariate.
Due to ...
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1
vote
0
answers
18
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How to Analyze and Interpret Between and Within Variance in a Dataset with Measurement Errors?
I am analyzing air pollution levels across 5 firms. For each firm, I have daily air pollution measurements taken over 5 days. My goal is to evaluate the variability of air pollution levels between ...
- 155
4
votes
2
answers
41
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Accounting for non-independence and autocorrelation in HGAM
I am currently trying to fit a HGAM to model differences in daily activity patterns of fish in two treatments. Data were collected with high-resolution telemetry, and I currently have estimates of ...
- 105
0
votes
1
answer
17
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Looking for appropriate model to run on SPSS while accounting for multiple measurements on same subject
I have two groups (Group A and Group B) that have different baseline characteristics. All subjects go through 5 different weights (twice each) and an outcome variable is measured. The table below ...
0
votes
0
answers
22
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Derive gamma-parameters from preset R^2 in mixed models
For a simulation study in R, I want to select the effect sizes according to a preset $R^2$.
Consider this two level random intercept mixed model, with one L1 predictor $X_{ij}$ and one L2 predictor $...
- 153
0
votes
0
answers
14
views
Random slopes in a linear mixed-effects model
In my experiment, I have 3 conditions for 100 participants (N = 100):
CHOICE: a number between 0 and 30.
EMOTION: a number between 1 and 7 or between -250 and +250.
PERFORMANCE: mean reaction times.
...
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2
votes
1
answer
63
views
Should date be a random variable in a mixed model, or included as an interactive term with my categorical variable?
I'm concerned with the effect of herbicide on percent cover of weeds. I've included a small dataset below. Initially, I thought to use the mixed model:
...
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1
vote
1
answer
48
views
Estimating mixed model with identical response value but different covariate values within a pair
Say we have a dataset with individuals. Each individual performed a task, either in solo or with another individual (variable condition), and we measured the ...
- 65
0
votes
0
answers
9
views
Extracting individual level posterior class memebership probabilities in multilevel LCA
I am conducting a multilevel laten class analysis using the R package multilevLCA.
I have fitted the model using multiple steps (i.e. determining optimal number of classes as well as clusters). I now ...
- 1
1
vote
1
answer
37
views
Correct binomial GLMM for temporal trends in species occurrences
I have a dataset with 80 species which were sampled in about 120 water bodies at two time periods (historical / recent). Only presence/absence of the species in each water body is considered. The data ...
- 11
0
votes
1
answer
36
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What model for my data?
I have a problem where we want to compare 3 treatments (a standard one against 2 new proposals). For each treatment we produce 5 objects. Each object is then divided in smaller parts and from each ...
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6
votes
1
answer
125
views
Is there a way to forecast by subgroup without forecasting each subgroup separately?
I am trying to find an appropriate model to forecast the number of applications received at the end of a recruitment cycle based on previous recruitment cycles and the number of applications received ...
0
votes
0
answers
10
views
DHARMa bootstrap testOutliers unexpected p-values
I am checking the assumptions of multiple univariate logistic mixed models each with a predictor and covariates.
Due to the following error:
...
- 1
7
votes
1
answer
280
views
How to model data with "super failures"?
In the radial arm water maze, an animal is placed in one arm of an (in this case) 8-armed maze with bait in one other arm. After some training, the animal is then observed making further attempts. A ...
- 1,291
1
vote
0
answers
29
views
Nested design with fixed and random effects: Is my R model correct?
I am trying to analyze a nested experimental design in R, but I am unsure whether I am approaching it correctly. I have a following data:
Set
Sample
Repet.
Response
1
1
1
y1
1
1
2
y2
1
2
1
y3
1
2
...
- 11
0
votes
0
answers
42
views
LMM: effect of day may differ between subjects - fixed or random effect?
We tested 12 animals in a test with three phases (a/b/c) in three conditions (C1/C2/C3) on nine days, i.e. every animal experienced each condition three times. On each day, four animals were tested in ...
- 13
2
votes
1
answer
25
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R what is the best glmmTMB model family to fit positively skewed index data
I am attempting to create a linear mixed effects model (lmer) with an positively skewed index dataset (1-4) that results in the best fit (distribution pictured below code).
Database
...
- 221
0
votes
1
answer
55
views
Single outcome, repeated covariates in time: linear mixed models?
I have a dataset where I want to predict an outcome (EDSS at last follow up, measured in a numeric scale which is from 0 to 10, including only .5 decimals). From each patient, I have exactly 2 ...
1
vote
0
answers
48
views
Opposite results using Bayesian (STAN) vs Multilevel model (nlme). How is this possible?
My datasets contains the median wages and the cumulative installed wind-capacity for 4000 counties over a period of 20 years. The wages tend to rise over the period and the capacity tends to highly ...
- 11
1
vote
0
answers
69
views
simr Failing to Run, "observed power calculation"
I am analyzing simulated delay-discounting data. The response variable is reaction time in milliseconds. K is the scaling factor describing how much value is affected by delay. College Year is from 1-...
- 11
1
vote
1
answer
36
views
R issue with the same random effect variance value (sigma^2) in sjPlot::tab_model() for two separate glmmTMB models
I have two glmmTMB models fit with binomial distributions that I am attempting to display their model summary output using sjPlot::tab_model()
Databases, Models, and tab_model() code
...
- 221
0
votes
0
answers
18
views
How to Forecast Sales for Sub-Locations Without Historical Proportion Data?
I have a time series dataset of total sales for a product in a store over time. This product is available in two different locations within the store: one stand near the checkout and another stand in ...
1
vote
1
answer
39
views
How much missing data in the output variable is OK when using Linear Mixed Models?
I have repeated-measures data, but due to missingness, I plan to use linear mixed models. My only predictor is Time, and my outcome variable is a Happiness Score measured quantitatively. The goal is ...
- 111
2
votes
1
answer
24
views
LMEM - When is it okay to not treat repeated measures as a random effect? And other related questions
Design: I have 3 groups, each subject was tested 3 times (3 trials) per time point, on three different time points.
The Independent variables are: Group (A,B, or C), Trial (1, 2, or 3), and Time (0, 2,...
- 55
0
votes
1
answer
29
views
Mixed model with raw data vs. linear model with aggregated data
I have a designed field study in which 4 treatments (Tx = CT, RT, RL & TS) were applied in 4 blocks (Bk A-D). Measurements were taken in 4 places in each experimental unit; some measurements ...
0
votes
0
answers
33
views
Observations within a level of fixed effect have the same level of random effect
My study aims to compare human performance with model performance on math tasks.
Here's the setup:
There are 700 unique assignments. 6 random human participants were recruited to work ok each ...
- 1
3
votes
1
answer
50
views
Comparisions between REML and ML
I have two questions and really appreciate your answers.
If Maximum Likelihood (ML) and Restricted Maximum Likelihood (REML) methods have the same fixed effects in a model, are the results from these ...
- 31
0
votes
0
answers
24
views
Multilevel Model in R
I have data from a study in which 19 participants (9 males, 10 females) have each completed 4 jumping conditions (BW, 20, 25, 30) whilst I have measured joint level data for the hip, knee and ankle. I ...
- 1
0
votes
0
answers
21
views
Error experienced when using mixed-effects random forest (MERF) in LongituRF
I have been using LongituRF to run mixed-effects random forest models, and have a question RE the predict.longituRF() function.
I have created a MERF using training ...
4
votes
1
answer
218
views
Is LMM a good alternative for Repeated Measures ANOVA with Missing Data?
Our study aims to assess whether there has been an increase in overall happiness among participants who used our interventions—such as dance classes, art classes, meditation, and other resources—...
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2
votes
0
answers
40
views
How can I convert an effect size from Cohen's d to f(v)
I am interested in calculating the power I need to compare several groups to one reference group in how much an outcome changes between two timepoints. My understanding is that I should use the ANOVA: ...
- 413
0
votes
0
answers
27
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Comparing different timepoints of measurements (1,2,3,4) for a group of individuals who survived vs. not survived
In most cases we have a time series based measurement (CD8T) for a group of individuals who survived or not survived (Survival) from a disease (repeated measurements). The timepoint based measurements ...
0
votes
1
answer
42
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CWC(M) in multilevel modeling
I am new to multilevel modeling and recently learned about CWC(M) by Zhang et al. (2009, https://journals.sagepub.com/doi/abs/10.1177/1094428108327450). I am running a multitlevel moderated mediation ...
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2
votes
1
answer
47
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Repeated Measures ANOVA/Linear Mixed Effects Model and Missing Data
I'm conducting a study measuring happiness across 4 time points, aiming to determine if there's an increase in overall happiness. The required sample size is 24 for four time points and 28 for three. ...
- 111
1
vote
1
answer
69
views
Estimating regression coefficients where the Fisher Information is $0$?
I have a basic linear mixed-effect model:
$$ y_{ij} = X_{ij}\beta + Z_{ij}b_i + \epsilon_{ij} $$
Where:
$y_{ij}$ is the j-th observation for the i-th group
$X_{ij}$ is the fixed effects design ...
- 433
1
vote
0
answers
32
views
Would it be okay to have a predictor that overlaps with the variable used as a random effect?
I will work with a predictor based on a Countries' Tightness index (numerical), so there’s one value for each country. I'll be collecting data in 50 countries, but I expect the number of participants ...
- 375
2
votes
1
answer
29
views
Fixed Effects vs. Random Effects in Panel Data with a Time-Invariant Main Variable
I’m working with panel data and planning to use a fixed-effects model. However, my primary variable of interest is time-invariant, which I can't include in a fixed-effects model.
I have two questions:
...
- 347
8
votes
1
answer
609
views
Confidence intervals in beta regressions
I am using a mixed-effects beta regression model in my study because my values are bounded between 0 and 1. When I run the same analysis using a linear mixed-effects model, I obtain similar results (...
3
votes
0
answers
50
views
Why does a random term in a large GAMM model make the curves spiky and wiggly?
I am creating several GAMM models with similar structures to dynamically model an acoustic parameter across realizations from multiple subjects, who are included as random smooths in my models.
In the ...
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2
votes
1
answer
33
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Correlated groups: mixed effects as a factor model
This has already been posted in quant exchange, but there's been no interest, so I thought I might repost it here.
I am trying to build a fundamental factor model in the style of Fama-French. I have ...
- 349