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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4
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1answer
4k views

How do I set up an unbalanced repeated measures analysis in R?

Context: I am analysing some impact assessment data (measuring invertebrate richness in response to pollution), but they are unbalanced - there are not data for every site at sampling occasion, and ...
3
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1answer
936 views

Wrong results using ANOVA with repeated measures

I am using ANOVA with repeated measures to test significance between males and females results of an experiment during which participants had to evaluate 7 stimuli in 2 conditions (EXP1 and EXP2). ...
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3answers
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Paired permutation test for repeated measures

I have a data set consisting of interactions between male-female dyads within a group in two conditions. The values range from -1 to 1 and indicate how responsible the female was for maintaining the ...
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1answer
1k views

Tests for consistent measurements and outliers

I have 3 experiments, where some quantity was measured 3 times. Thus, 3 biological replicas, 3 technical replicas in each biological replica, 9 measurements in total. I need to answer the following ...
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2answers
3k views

Permutation tests with repeated measures

Although reading quite a bunch of books, I'm still not sure, which method to use and how to implement it, therefore I appreciate any help! I have 4 different groups (treatments) with 50 participants ...
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0answers
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How to use G Power 3 to calculate statistical power in mixed design ANOVA with unequal group sample sizes [closed]

In G power 3, ANOVA repeated measures within-between interaction: Only the total sample size is reported assuming equal sample size for the two groups. My questions are: How would it work if the ...
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0answers
303 views

Is repeated measures ANOVA appropriate for my experiment and is my sample size large enough?

I'm really confused. I never took statistics but am trying to read up as much as I can. I didn't think much about statistical analysis until after doing the experiment, unfortunately, but maybe ...
8
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1answer
2k views

How to analyse repeated measure ANOVA with three or more conditions presented in randomised order?

Context: My question concerns a typical design in my area – a researcher takes a group of subjects (say 10) and then applies three different conditions to them to measure the change in a response ...
6
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1answer
9k views

Friedman's test and post-hoc analysis

I am carrying out a statistical analysis for my research. I am using a Friedman's test with post hoc analysis. At present I am using the function ...
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1answer
23k views

Sample size required for mixed design ANOVA to achieve adequate statistical power

Context I ran an experiment with 3 x 2 design with three levels of within subjects factor (repeated measures) and two levels to the between subjects factors. I ...
3
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2answers
1k views

Best model for change in scores over three time points

I have a response variable measured at three time points per individual (week 0, 18, and 36). I am interested in differences in the change of the response over the 36 weeks within some categorical ...
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1answer
831 views

Can slopes in linear regressions be used as the independent or dependent variables in other regression models?

I have 100 patients and each patient have 10 longitudinal serum creatinine measurements. The estimated glomerular filtration rates (eGFR) were calculated from a MDRD formula comprising gender, age and ...
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1answer
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Is MANOVA the correct way to handle multiple response variables that are additive?

Context: I am trying to analyze an experiment on plant community response to two treatments. Here’s a simplified description of the experiment, there are a few extra complications in reality. ...
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2answers
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Effect size of Cochran's Q

I have performed a Cochran's Q test for a within-subjects experimental design with 3 conditions and 36 participants with a dichotomous dependent variable. I found a (just) statistically significant ...
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3answers
414 views

Mouse models - 'replicates' and analysis

I'm hoping to hear from someone who has worked on mouse models or similar biological analyses where there is a tendency to run 'replicates' of an experiment. I know multiple testing is a sizeable ...
4
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1answer
247 views

Is there literature on staggered within subjects designs? What are the consequences of such a design?

I am creating a term to describe a design that may not be the proper term ("Staggered within subjects design"). What I mean by this is one can imagine a within subjects design with 3 levels. Each ...
4
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1answer
715 views

Some doubts about using GLMM

I'm analyzing the results of a hormone manipulation experiment. I measured a number of variables at three times in three groups. The groups are different sizes and not all individuals were measured ...
4
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2answers
5k views

Count data with mixed effects

EDIT: Thanks for the help so far. I have updated the question based on further work. I am interested in finding any difference in response of counts of two competing species to dryness and elevation....
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2answers
470 views

Check of R command and output of unbalanced repeated measures ANOVA

I'd love a check if anyone is willing! I am trying to see if there is a statistical difference in female size between sites. Over the years females were repeatedly sampled within sites. I have ...
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1answer
95 views

Is there a classification of physical measurements according to their statistical distribution?

I am looking for a document or research articles classifying physical or chemical measurements (or perhaps better means of measurement) according to the reference statistical distribution and ...
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2answers
1k views

Repeated measures with correlated measures (not time)

Most repeated measures ANOVAs have time as the repeated measure; I was wondering about using a repeated measure that is not time. Say we fed two groups of animals different diets. At the end of the ...
4
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1answer
899 views

Boxplot with glme

I am examining the difference between a physical feature of different species of animals. Due to the nature of my experiments I'm using a nonlinear mixed model with the following setup: ...
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1answer
2k views

How to estimate correlation among repeated measures?

I want to carry out a power analysis on a one group repeated measures experiment using G*power. I have a group of subjects who tested a set of products. Each subject test one time the products. Hence,...
2
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2answers
632 views

ANCOVA with multiple instances of the between-subject covariate

If I find that my covariate (reaction time) alters over the length of my experiment (e.g. due to fatigue), can I somehow build that into my model? So what I am saying is that the effect of my ...
4
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2answers
355 views

How to deal with a specific case of unbalanced within-subjects design?

I have a completely within-subjects design with 3 independent variables: Trial type (3 levels) Task order (2 levels) Modality (3 levels) However, for one of my levels of Trial type, the Task order ...
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2answers
10k views

How to set up a two-way mixed ANOVA with a covariate in SPSS?

I wanted to carry out a two-way ANCOVA for my data. However, SPSS isn't liking that I have only one IV. I have One IV: Group (3 levels, i.e. 2 experimental groups and a control group), One DV: ...
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2answers
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Analyzing a 2x3 repeated measures design using a logit mixed model

An experiment I conducted recently used a 2 (between participants) x 3 (within participants) design. That is, participants were randomly allocated to one of two conditions, and then completed three ...
14
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3answers
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What is the difference between using aov() and lme() in analyzing a longitudinal dataset?

Can anyone tell me the difference between using aov() and lme() for analyzing longitudinal data and how to interpret results ...
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2answers
656 views

Repeated measures using R [closed]

How do I carry out a repeated measures analysis using R?
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0answers
555 views

What is a good statistical test for independent replicates?

I have a series of measurements in which something is sampled and placed into either category 1 or category 2. I have 3x2x3 factors for each set of measurements, and each set of measurements is done ...
12
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2answers
7k views

Split-Plot ANOVA: model comparison tests in R

How can I test effects in a Split-Plot ANOVA using suitable model comparisons for use with the X and M arguments of ...
3
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1answer
349 views

Does a within-subjects factor with unequally represented levels mess up a repeated-measures ANOVA?

Is there any downside to using a repeated-measure ANOVA when you have a within-subjects 2-level factor where 1 level is represented by more trials than the other. I know in ANOVA we are comparing ...
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1answer
484 views

Regression with repeated data

I have a question regarding regression analysis on a dataset were the input values generate different results over time: e.g. 1 2 2 2 3 5 4 1 2 5 3 8 How would ...
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2answers
3k views

Consequence of violating independence assumption of ANOVA

I would like some help with the following problem. I have 40 subjects. On each subject I take a measurement at 25 body sites. The measurement is a continuous variable that varies between 0 and 1 and ...
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5answers
9k views

Testing the normality assumption for repeated measures anova? (in R)

So assuming that there is a point in testing the normality assumption for anova (see 1 and 2) How can it be tested in R? I would expect to do something like: ...
3
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2answers
3k views

How to solve a case of unbalanced repeated measures?

I have animals, that could be virgin or mated (reproductive state is the fixed factor), which I've stimulated sequentially with 4 different doses of an odour (doses are the repeated measures, the same ...
9
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1answer
2k views

How should I analyze repeated-measures individual differences experiments?

I do quasi-experimental individual differences psychology research. I examine how people who differ in a cognitive ability (that I measure) perform on another task that always at least involves within-...
9
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1answer
2k views

Sample size for proportions in repeated measures

I'm trying to help a scientist design a study for the occurrence of salmonella microbes. He would like to compare an experimental antimicrobial formulation against a chlorine (bleach) at poultry ...
7
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2answers
462 views

Taking advantage of many pre-treatment measurements

I am planing a pre-post treatment-control design study with a large number of pre-treatment measurements. I have subjects divided into a control group and a treatment group. For both groups, I will ...
6
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3answers
6k views

How do I setup up repeated measures data for analysis with nlme()?

I'm trying to transition to R from using SPSS. In the past, I've setup my data in the wide format for my repeated measures ...
35
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1answer
37k views

Multiple comparisons on a mixed effects model

I am trying to analyse some data using a mixed effect model. The data I collected represent the weight of some young animals of different genotype over time. I am using the approach proposed here: ...
17
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1answer
16k views

Unbalanced mixed effect ANOVA for repeated measures

I have data from patients treated with 2 different kinds of treatments during surgery. I need to analyze its effect on heart rate. The heart rate measurement is taken every 15 minutes. Given that ...
4
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2answers
3k views

Compare treatments on mean difference between two times

This sounds like an easy setup, and I'm absolutely sure it's not too complicated to do, but somehow I can't figure out how to approach this. The setting is as follows : There are 6 treatments with 16 ...
10
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2answers
422 views

Longitudinal comparison of two distributions

I have the test results of a blood test administered to 2500 people four times at six-month intervals. The results primarily consist of two measures of immune response - one in the presence of ...
32
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5answers
9k views

Modelling longitudinal data where the effect of time varies in functional form between individuals

Context: Imagine you had a longitudinal study which measured a dependent variable (DV) once a week for 20 weeks on 200 participants. Although I'm interested in general, typical DVs that I'm thinking ...
8
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1answer
6k views

Determination of effect size for a repeated measures ANOVA power analysis

This is a follow-up to the repeated measures sample size question. I am planning a repeated measures experiment. We record energy usage for 12 months, then give (a randomly assigned) half of the ...
6
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3answers
1k views

Might be an unbalanced within subjects repeated measures?

I ran a within subjects repeated measures experiment, where the independent variable had 3 levels. The dependent variable is a measure of correctness and is recorded as either correct / incorrect. ...
14
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1answer
34k views

How to determine the sample size needed for repeated measurement ANOVA?

I need some help about repeated measurement ANOVA. We are investigating the effect of some intervention on reducing blood stream infection (BSI) rate in some wards. We plan to capture the BSI rate ...
14
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2answers
3k views

What would a confidence interval around a predicted value from a mixed effects model mean?

I was looking at this page and noticed the methods for confidence intervals for lme and lmer in R. For those who don't know R, those are functions for generating mixed effects or multi-level models. ...
10
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1answer
973 views

Estimating variability over time

I have a dataset that contains ~7,500 blood tests from ~2,500 individuals. I'm trying to find out if variability in the blood tests increases or decreases with the time between two tests. For ...