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Questions tagged [repeated-measures]

Repeated measures data occur when more than one measurement is collected on the same unit (e.g. subject). Use this tag for RM-ANOVA together with [anova] tag.

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Using GLMM to explain vegetation change as a function of change in soil parameters

I have a dataset that consists of vegetation datasets (species/abundancy tables) and soil parameters (tested for ten parameters per soil core). Three different rounds of these data are recorded in ...
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Repeated measures anova with 3 groups

I have a dataset with 3 groups Tuni, Sal, and Ohda. I have two timepoints for each, time 30 and time 60. I want to do a repeated measures ANOVA with posthoc tests for group*time in SPSS. I have also ...
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testing normality in repeated measures

For my bachelor thesis I collected data. I have a within subjects-factor (2 levels) and a covariate. I am using SPSS. When I want to check normality of my sample, I know I need to do that with the ...
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Help modeling rjags 2x2 logistic model with subjects and items as random intercepts (Bayes)? [on hold]

I'm trying to set up a Bayesian 2x2 logistic GLM model in rjags. would like to see if I have set up everything correctly (are the priors reasonable, is the GLM reasonable?). Below is the model in ...
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Post-hoc test on linear mixed effects analysis comparing two treatments over time

I am trying to analyze my data in R and I would like to ask, if what I have done so far makes some sense, and how I could proceed. Let me try to explain my data first: I have two different treatments ...
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Repeated Measures ANOVA with two factors

I have 300 patients with heart problems (2 groups/types of problem) that have completed the questionnaire SF-36 (8 scales), before and after the surgery. Some of them have been attending sessions with ...
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Overall effect of time in mixed model before looking at individual time points

I have a mixed model using factor(time) as fixed effect and subject as random effect. So the format is like this: ...
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Simple-Effects Test for Unbalanced Mixed Design ANOVA

I am working on an Open Stats Lab activity for factorial ANOVA and have posted my analysis on GitHub. Once I have a significant interaction, how do I conduct a simple-effects test in R? The mixed ...
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Comparing time periods from frequent repeated measures

Simple scenario: We vaccinate animals with two different vaccines (groups A and B, with a negative control C), infect them with the pathogen, and measure many parameters including a daily temperature ...
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Methods to account/correct for dropouts in intervention study

I have depression scores for patients before and after intervention, there is no control sample. I want to assess if demographics have an effect on recovery, and I was thinking of doing a linear ...
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Mediation analysis with depent observations. Is it possible with mixed models?

I wonder whether it is possible in principles to conduct a mediation analysis with dependent measures. The problem is of course that we are violating the assumption of independence of observations. ...
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Interpretation of coefficients in linear regression of data in repeated measure

I have the following data in the repeated measure : ...
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How to account for different numbers of trials for percentage data in R?

I'm trying to figure out a correct way to set up a linear mixed model (or similar) for a decision-making experiment. Design was as follows: 2 x 2 within-subjects DV: count/percentage More ...
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What is the origin of the Winer's compound symmetry test of the variance-covariance matrix?

In his famous book, Winer (Statistical principles in experimental design 1971; reedited Winer, Brown, Michels, 1991, p. 517) introduced a test of compound symmetry. The test expands on the likelihood ...
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Repeated measures ANOVA sample size calculation using R

I'm trying to conduct a sample size calculation for a repeated measures ANOVA. The study will involve taking 10 measurements from participants. Prior to each measurement, participants will be ...
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Singular fit (or not) for 2 seamingly identical mixed effect models and questioning the validity of a random intercept

This is a follow up question to this first question : First question I have two seemingly identically structured datsets ...
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Paired t-test following main effect of mixed model with missing data

I am analyzing data for a repeated measures study with missing data. For example here is a 3 X 3 experimental design with three conditions and 3-time measures: I am using a mixed model for the main ...
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SPSS or R: Correlation between two variables over time?

I hope you can help me or give me any hints - any keyword for me to look into is appreciated! I have conducted an experiment (user study) with 3 measurement times and 2 variables (for each time point)...
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Appropriate model for repeated measures in R (Effect of treatment)

I would like some advice on what statistical model I can choose and how to implement in R. I have 2 groups of high blood pressure patients (each group consists of 40 subjects ), a treatment group (...
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What is the anova variation of a paired t-test in my case?

I have the following case: I inventoried birch trees in 10 areas, once in 2000 and once last year (same areas inventoried in both years). If I want to see if there is a difference in the average ...
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Does reversing a covariate change the within-subject effect in a repeated measures ANOVA? Why?

I noticed I coded a variable in the wrong direction, so I reversed it. I thought this reverse would not matter for drawing inferences from the ANOVA analyses (e.g., p-values or effect sizes) as there ...
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What is the correct number of measurements and groups in the following Design?

I using GPOWER: "Anova repeated measures within factors" and need help in giving a correct number to the following inputs: Number of groups. Number of measurements. The design is as follows: I have ...
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Analysis question for repeated measures data

I am conducting a survey wherein people are offered different hypothetical amounts of money (8 ascending values) to complete a task. For each value, people rate how motivated they would be to complete ...
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Two-way RM in R lacking p-values

I'm attempting a two-way repeated measures ANOVA in r studio, to analyze the effects of foliage age (old vs. new) and time (months 4-9) on the concentration of a chemical (phenolics) in plant tissue. ...
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within-subject regression analysis

I have three levels (suppose A,B, and C) in my experiment and wish to do within-subject regression analysis. All the 3 levels are manipulated within-subject. Also A is outcome category, B is outcome ...
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RM ANOVA: time as continuous or categorical?

I am using the lme() funtion in R (from nlme package) to perform a Repeated Measures ANOVA. Here's the formula ...
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Two different approaches to repeated measure data analysis

My research is intended to see the difference in people's responses to sad vs. joyful faces. I have gathered 10 faces, 5 sad and 5 joyful, and I have recruited 100 participants for my research. I ...
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Single DV with repeated/clustered measurements of IV

I have an analytical dilemma wherein I have a single DV with multiple categorical and continuous IVs (one of which is a continuous IV that has multiple measurements across time). I'm not sure the best ...
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Correction for Multiple rmANOVAs followed by Post-Hoc tests

I'm researching the effect of one IV on four DVs which don'f form a structure. So I can't use a MANOVA approach. I'm using a repeated measures approach. Instead i would use four univariat ANOVAs. For ...
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Can someone tell me how the variance-covariance matrix is being made in this repeated measures simulation? [closed]

I found this tutorial for simulating repeated measures data, but I have no idea what "stdiff" is and why it's set equal to 9. Anyone know what's going on with how the var-cov matrix is made? http://...
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Why does ignoring dependencies between observations *inflate* my standard errors?

In the introductions to books and review papers about modeling dependent (a.k.a., within-subjects, repeated-measures, clustered, longitudinal, hierarchical) data, it is very common to say that ...
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GEE vs. fitting a simple model to each subject and then test the parameters across subjects

In my experiments, participants (N=50) are asked to play a decision-making game several times. I am interested in testing whether a certain factor "F" (present/absent) influences participants' ...
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Repeated Measures to Create Bigger Dataset for ML?

Background: I work for a small health center, and we're interested in predicting adverse events like hospitalizations. We are not interested in generalizable knowledge (effect sizes of predictors, ...
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rmcorr package with changing correlations

I was looking at the rmcorr package in r for repeated measures correlation and have read the paper on it: Bakdash JZ, Marusich LR. Repeated Measures Correlation. Front Psychol. 2017;8:456. Published ...
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within vs between subject variability:LME?

I have multiple time points of data for my subjects and would like to look at a individual variability measure and see if that has a different associations with my predictor than the between-subject ...
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merit of t-test vs repeated measures

In a cohort study, patients have been enrolled for a new method of treatment of a condition. The measurement of interest, for example, tumour size is taken at baseline (BL) ie before treatment, the ...
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Repeated measures on subjects without all subjects present in each period

I am working on a dataset in which several individuals were observed over several periods. However not all individuals were observed at each period. Due to repeated measures on individuals I have to ...
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Compare groups with repeated measures presence/absence data

I read about cochran's Q and don't think it is right for what I am trying to do. I created and example of my data. I have 5 ecosystems, each of which had 3 sampling locations (plots). I wanted to ...
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Paired-t test for comparing two subgroups selected from the same underlying population?

Say I have a total population of N=100. Algorithm #1 is based on some predictors and it selects n1=10 subjects (i.e., subgroup #1). Algorithm #2 is based on another set of predictors and it selects n2=...
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what statistical test to use in comparing class grades (A, B, C)? How to use GraphPad PRISM for doing so?

we've got 2 school classes. each class have 15 students. each of them had 3 tests, and got A, B, or C grades. (Note: 2 of the students just did one of the tests, so we have missing data). which ...
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Statistical analysis techniques for pre and post repeated measures

I am trying to understand which is the appropriate statistical technique to use for the below experimental design: Design: I have two groups - an intervention group (that took an action, eg increased ...
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What is the difference between cross-over and repeated-measures designs?

I know that a cross-over experiment (of any number of treatments/levels) necessarily has a repeated-measures design, but that not all repeated-measures designs are cross-overs. However, I wasn't able ...
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Best way to model repeated measure differences across groups

Let's say I have three groups, each consisting of two individuals. Each group answers questions together, and each member independently reports their confidence in their groups' answers. I want to ...
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Analysing pre and post treatment within one group plus two control groups

Basically, I have a mixed design, with 3 groups (between subjects), and 13 personality traits (within subjects). However, one of the groups has pre- and post- scores. There was a fictional character ...
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2answers
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What statistical tests can I use? Repeated measures design, two groups, each is control and experimental at different points in time

I need to determine if an intervention had an effect. In the experimental design, measures were taken at three points in time: pre-test, post-test #1 and post-test #2. One group (group A) received the ...
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1answer
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How to determine change in effect over time?

I would like to determine if the effect of binary variable (like gender) on a continuous variable (like a reaction time in ms) can change overtime (between T1 and T2). I have over 100 subjects. What ...
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Is it possible to fit repeated measure data to Gaussian density curve

I collected my data (insect biomass) fortnightly from the same trees (six trees) from February to August. The biomass curve looks like Gaussian density curve. I know that I can use optim() to fit the ...
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Propensity Matching in Longitudinal Studies (with independent participants)

I am trying to generate a set of matched samples from a longitudinal study. However, I would like the matched pairs to be from independent individuals, and as soon as a pair of samples are selected, ...
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What statistical analysis? [closed]

I have 4 groups in which C is a control group that had no surgeries but sampled the same as other groups. A, B and C had different rumenotomy techniques of surgery. Each group had 3 males and 3 female ...