Repeated measures data occurs when more than one measurement is collected on the same unit (e.g. subject). This data cannot be analysed through normal methods because the rows in the data are not independent due to the multiple measurements. The time sequencing of the measures may not be important.

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Conduct mediation and moderation in within subject design

I was wondering if someone could help with how to conduct a moderation analysis and a mediation analysis in a within subject (repeated measures) design? I am familiar with the Judd, Kenny, McClelland, ...
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25 views

Test for repeated measures with large numbers of missing values

I have a number of independent continuous variables, such as HbA1c, waist circumference, total cholesterol measured in approximately 300 people over various time points (baseline, 3, 6, 12, 24 months ...
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9 views

What statistical test should be used to compare two independent sample over time (pre- and post-test) for categorical variables?

I have baseline and follow-up surveys, asking the same 33 questions. A typical question is: How well do you think your family knows what you are good at? Very Well Well ...
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24 views

Analysis of reaction times with missing data by trial/item

I have a developmental psychology study with one between factor (age) and two within factors (scale-3 and difficulty-2). I recorded reaction times but have eneded up with a lot of missing data for the ...
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1answer
21 views

May I analyze this kind of data with ANOVA?

I have the following kind of experimental setup. There are two different tasks (say A and B) the participants are performing. Each task is performed thrice (three times) by each participant. There is ...
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1answer
37 views

Repeated measures but not longitudinal: A case of multivariate LMM or repeated measures LMM?

I am trying to get my head around the question of what kind of model is most appropriate for the following data: Every participant rated 14 written statements in terms of various aspects (e.g. ...
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1answer
56 views

Repeated measures study with a covariate

We conducted a study where we are measuring perceived tiredness at different intervals (a total of 10). We recorded a score before starting the experiment, as a covariate to account for differences in ...
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25 views

How to describe this model

I have a study where subjects have received treatment to one eye, the other eye is untreated and is acting as a control. There are 3 measures (of retinal thickness) taken in each eye. The model I am ...
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9 views

Account for Repetition in Experimental Design when testing variants of an image

In my experiment, an image is presented in five different ways to the test person. The person then has to do some task like "point to the red flower in the image" and I measure the time taken to check ...
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1answer
24 views

repeated-measures linear mixed-effect model

I have two soil treatments: CT and NT. For each treatment, I have 11 CO2 measurements taken in 7 times, i.e. 11 "replicates" for 7 dates. I'd like to evaluate if the measurements are different in ...
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Applying Friedman Test on percentage of binary outcome

Is it correct to analyse data as described in the following? N Participants were asked to watch different videos showing the outline of a hand grasping an object. Four different types of hands were ...
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2answers
44 views

Is repeated measures or mixed model ANOVA necessary for this analysis?

I've spent a long time generating and analyzing a dataset and now it comes down to the statistical analysis... and I'm not sure how best to proceed. In my dataset, I have rats sorted into one of 4 ...
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15 views

Analysis of measures of difference

Let's say I want to measure the width of a road using a measuring tape. I've drawn a crap diagram here: Rather than measure the distance directly, I decide to be obtuse and measure the distances ...
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21 views

How to analyze differences between two time series collected under two different conditions

How should one analyze time series data that were collected during two seasons: season 1 and then at season 2, where during each season a measurement sample for several continuous variables were ...
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25 views

Reporting the results of a mixed within/between subjects permutation test

I am doing some hypothesis testing on the results of an electrophysiology experiment. I have electrical recordings of the rate of fire from two different populations of neurons (let's call them ...
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21 views

What would be the best analysis / analyses for the over time coral bleaching recovery data?

I am analyzing this MISeq microbial community data with Phyloseq and vegan R-packages from coral hosts and I would much appreciate some help and ideas as this is my first analysis of this kind. We ...
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1answer
21 views

Within subject effect size when no correlation available

I am doing a research project on the topic of replicability in psychology. To do this, I did a set of 10 meta-analysis on different studies. My problem is the following : some of those studies were ...
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4 views

Greenhouse-Geisser correction vs Non-independence

In repeated-measure ANOVA, Greenhouse-Geisser correction is commonly used to handle sphericity issues (when there are more than three levels in a condition). But does it deal with data that violate ...
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30 views

R: lme vs ezAnova: Different degrees of freedom for two-way ANOVA with repeated measures

I'm trying to run a two-way ANOVA repeated measurement with (1) lme and (2) ezAnova. The problem is that I get different degrees of freedom of the denominator (denDF...
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8 views

4 groups | 3 measurement points | SPSS

We are performing a RCT with 4 groups (1 control + 3 experimental), where we measured physical activity (PA) in 3 moments (at baseline, post-test and follow-up). Although we have done stratified ...
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11 views

How can I compute a required sample size for a multiple logistic regression with repeated measures

I ran a study using multiple logistic regression with repeated measures (3 predictors- 2 are dichotomous and 1 is continuous, 64 observations per participant), and now I want to compute an effect size ...
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3answers
98 views

Mixed-effect model in R using lme for data count data with two fixed effects and repeated measures

I have no idea how to analyze this dataset. I am asking if two genotypes, T and M, respond differently to a treatment, E2 (I also have a control, CON). All 36 animals were given both E2 and CON in a ...
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13 views

Literature (guidelines) on unbalancedness in two-way within-subject ANOVA

I am looking for literature (guidelines) which discuss the consequences of unbalanced designs on running a (two-way) within-subject ANOVA and pros/cons of various counter-measures. I came up with ...
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14 views

Pairwise comparison of stats with repeated measures

I have a data set of participants with four sets of test results, two pre- intervention and two post. So far I've been averaging the two test scores and using a paired t-test to compare the results, ...
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7 views

Formula to convert test-retest reliability into SD of difference

Wanting to work out the statistical power of a repeated-measures t.test. This requires an estimate of the SD of differences within pairs (the correlation between measures for a given person is what ...
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1answer
57 views

How to run an ANOVA when there are multiple repetitions

I have a 2x2 repeated measures ANOVA (2 factors each with 2 levels). In addition each subject completes each condition multiple times (5 repetitions). So for example I would have Factor A, level 1 ...
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1answer
22 views

Poisson regression with robust error variance - cross sectional study

To estimate RRs in a statistical model with a binary outcome, sometimes the modified Poisson regression can be used (proposed by Zou). Specially in epidemiology, when the incidence rate of the binary ...
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12 views

2x6 repeated measures ANOVA interaction and main effects question

Currently I'm graduating and I'm finishing up my master's thesis as we speak. It's a study about the effect of hand positioning on response time. I'm submitting my data to a 2x6 repeated measures ...
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20 views

T-test or repeated measure ANOVA?

I am a Phd student in neuroscience and not so knowledgeable in statistics. I have done an experiment and am not sure if i should use repeated measures ANOVA or independent T-test. The experiment is ...
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19 views

SPSS | Repeated-Measures ANCOVA | Covariate

We are performing a RCT with 4 groups (1 control + 3 experimental), where we measured physical activity (PA) at baseline, post-test and follow-up. Although we have done stratified randomization, the ...
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1answer
24 views

Time as random effect or fixed effect in glmmADMB

I have a longitudinal dataset where patients have a measurement with a date, currently coded as time from end of treatment (days). Now, I want to build a model. Roughly, a zero inflated Poisson model ...
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19 views

Generalized estimating equations - Multiple binary responses per condition (spss)

I have a repeated measures design. Each participant has two visits, one on placebo, one on drug. The task has a number of conditions. 'Target' has 2 levels, MS and RNG. Within the Target condition ...
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13 views

Permutation test for repeated measures (in time)

I have the measurements of a quantity, observed every day for 60 days Usually, this quantity is really near to 0, apart from 3 days where it is (significantly?) greater than 0 I thought it would be ...
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31 views

aov() and lme() give completely different results in analyzing repeated measures

I have data consisting of two measures per subject (variable score, measured at Day 0, and Day1 per each subject). There are two groups, and each subject belongs to one of them (variable Group). I ...
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9 views

ANOVA with repeated identical acquisitions (subject+treatment+tests)

I'm just reviewing an analysis done by an ex-colleague and am struggling to figure out whether it's been done correctly or not. I'm also not sure how to exactly call the model they employed. ...
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26 views

Meta-analysis: Calculating variance/ standard error of a mean difference for a within-subject design

I'm currently doing a random-effects meta-analysis. The studies that I'm analyzing come from a within-subject design where the same participants complete both the experimental and the control ...
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1answer
50 views

Model selection: testing the need for random-effects terms in longitudinal data

I have longitudinal data set where each participant was observed for 12 weeks. I followed this paper: Bliese, Paul D., and Robert E. Ployhart. "Growth modeling using random coefficient models: Model ...
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1answer
23 views

Repeated measures ANOVA contrasts

I'm running a repeated measures ANOVA with a 3-level DV. Now what I've read is that you only look at the post-hoc test if the within-subject (overall) effect is significant. What about the within-...
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80 views

R vs SPSS - simple effects analysis in mixed 2x2 ANOVA scheme - same data, different results

I prepared a mixed 2x2 ANOVA design analysis both in SPSS and in R. The SPSS script is correct, but in R script there is a mistake somewhere. To test that I generated artificial data from a normal ...
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29 views

Setting Linear mixed model for within-subject crossed factors

I have problems in undertanding how to correctly run a mixed linear model. I have done an experiment to compare three groups (1 between-subject factor); for each subject, 2 sensory stimuli are given (...
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20 views

Unbalanced Repeated Measures Anova

First Question: I would like to double check that my code is doing what I think it is doing. I have two independent variables, Previous drilling and Soil Type, that are observational. Simpsons ...
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14 views

Which analysis is best for my data with repeated measures and 2 treatment groups?

I'm working in R. I have a data set of 21 fish, roughly half in each of 2 treatments. I measured their behaviour over 10 minutes and want to analyse this to look for changes over time (gradient) and ...
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1answer
33 views

Variance of Level 2 random effect depending on value of variable in highest level (Level 3) in Hierarchical model

I was reading material on hierarchical models, especially 3 level hierarchical models. One of the examples I found was having the hierarchy Hospitals-Wards-Nurses. Only 1 measurement per Nurse. So ...
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79 views

How to model a 2x2x2 dataset for a 3 way repeated measures ANOVA analysis

I have some data derived from a 2x2x2 experimental design. There are 3 IV's, each with 2 levels. My DV is reaction time (measured in seconds). I've used a repeated measures design (n=10). I have 20 ...
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17 views

What multivariate test to use when variables need to add up to a constant?

My data have three levels. The highest level is preferred vs. actual state. For each state there are 6 dimensions. Within each dimension there are 4 variables representing scores of 4 kinds of ...
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8 views

Increasing sensor resolution by repeat measurement

I have a thermometer which has resolution of 1C. The temperature is measured, the thermometer is reset, and the temperature is measured again. I'm looking for a formula to calculate how many ...
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22 views

Two way repeated measures with zeros, non integer values, and non-normal distribution

I would really appreciate some help with a few models I am trying to run. Essentially my data looks at how often a subject was visited depending on treatment and subject type across two years. The ...
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1answer
64 views

How to reconcile results from many incremental hypothesis tests?

I'm considering a series of controlled experiments (e.g. A/B tests) measuring the performance of a system. Each time a change to the system is found significant (via statistical inference) the test ...
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0answers
27 views

Why is the “sphericity assumption” in RM-ANOVA (constant variance of difference scores) called “sphericity”?

Why is the "sphericity assumption" in RM-ANOVA, i.e. the assumption of constant variance of difference scores, called "sphericity"? (This question was suggested in the comments to a related question.)...
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24 views

ANCOVA with ordinal covariate?

My study looks at the effects of sex on performance in a psychological task. There are 3 variables: sex (m/f), plus 2 within-subjects factors (with 2 and 3 levels), so it's a 2x2x3 repeated-measures ...