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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Repeated measures ANOVA in R for non-orthogonal design
I have data from a two-factor within-subjects experiment design where the conditions are not orthogonal. Factor one (Location) has three levels; factor two (Stimulus) has three levels, one of which is ...
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1answer
58 views
R: Greenhouse-Geisser in Anova from car package
i have a question concerning the output from {car} Anova. I want to run a simple 2x2 repeated measures ANOVA using the multivariate approach. I can run the (modified) example from the Anova {car} help ...
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18 views
Specifying a correct full model for an unbalanced repeated measures design in R lme4
Recently, I have done a fairly complex experiment, and I am having trouble coming up with a model that is suitable for the data. I have spent a few days reading about, e.g., when random effects should ...
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30 views
Difference between GLM with intercept of subject VS repeated-measures ANOVA? [SAS code]
I've spent days trying to determine the difference between these two methods, which, as best I can tell, represent the univariate and multivariate approaches to a within-subjects design. Can anybody ...
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2answers
99 views
Using lmer for repeated-measures linear mixed-effect model
EDIT 2: I originally thought I needed to run a two-factor ANOVA with repeated measures on one factor, but I now think a linear mixed-effect model will work better for my data. I think I nearly know ...
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1answer
28 views
Repeated-measures error in R ezANOVA using more levels than subjects (balanced design)
I'm having a problem running a repeated-measures ANOVA in R using the ezANOVA function.
I have data from 18 subjects - each subject participated in 3 conditions, ...
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67 views
What method is better to model percentage response with each subject measured two times and heteroscedastic error?
The response was calculated as $\frac{Control-Observation}{Control}*100\%$. Raw values of $Control$ and $Observation$ are not available, I have only calculated values. Each value was measured twice. ...
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1answer
39 views
What factor (trials or blocks) to use in a repeated measures ANOVA
I am conducting a psycholinguistic experiment. Each trial consists of the subject responding to a word by pressing a button.The design of my experiment is as follows:
5 blocks of a 100 trials each ...
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98 views
Multilevel modeling of experimental data with repeated measures in the same condition of factorial experiment
I'm struggling with modeling some experimental data using the lme4 package in R, and would appreciate input.
My experimental design is as follows: subjects ...
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15 views
How to test inconsistency / within-subject variance across time?
I have this dataset where I have DV measured over 5 time points for every subject (over about 30 subjects).
If I graph the values of individual subjects over time and look at them, there are no ...
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1answer
78 views
Lmer model design
My data is a series of repeated measures in time (14 measures). I am trying to model the variable HbA1c which is a blood test performed at each visit to measure the ...
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2answers
29 views
Experiment design with two groups, pre- & post- treament assessments
I am conducting an experiment with a control group and a treatment group. Both groups will take a pre and post treatment depression inventory. What statistical procedure do I use to determine if the ...
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20 views
Proper method for time-staggered/repeated measures data?
I have a data set with 300 workers/subjects. There is one dependent variable: a worker's performance, by some metric, during the current week. There are three independent variables (let's call them ...
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1answer
40 views
Modeling stimulus-response output
I am trying to analyse some data and I am a bit lost as to what is the correct approach to take.
The data are blood hormone levels, taken repeatedly from various subjects, after a certain treatment, ...
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1answer
45 views
How to analyze ordinal repeated measures data
I have data from an ordinal scale, with the score ranging from 1-4. Each subject has 9 assessments on this scale (study is a 9-way crossover design), and there are no missing data. What is the ...
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33 views
Book on Repeated Measure Analysis
Can anyone recommend a good book or some other reading materials
on repeated measure analysis using mixed model.Thanks.
Hanna
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20 views
Factorial design with repeated-measures and binary outcome variable
I have a question on how to analyze some data from a psychological experiment.
The design of the experiment is a mixed 2x2x4 factorial: the first 2 factors are manipulated between-participants, but ...
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1answer
31 views
Blocked repeated measures ANOVA in R
I am trying to test if richness varies by treatment (Severity) over time (Block) using a repeated measures ANOVA in R. Any suggestions on how to do this correctly? I have tried, but get an error ...
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34 views
Pretest-posttest plus control design
I am evaluating the effect of an intervention (treatment: a lecture) on the ability to spot behavioral clues of emotions using visual stimuli using pretest-posttest plus control group experimental ...
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32 views
Measuring relative variability for variables with different scales
I want to compare the relative variability of several sleep-related variables in the same group of subjects. For example, is there more variability in time spent in REM sleep compared to the number of ...
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1answer
46 views
Cronbach's Alpha and Factor Analysis for Repeated Measures Design
I have a repeated measures (time 1, time 2) experimental design and would like to run a confirmatory factor analysis on the scales I've used and to follow up with a cronbach's alpha. However I am ...
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1answer
21 views
BMI at baseline & followup with exposure at baseline; model change or BMI at FUP? Control for BMI baseline?
For a prospective occupational cohort where everyone is exposed to one or more chemical agents, examining BMI at follow-up compared to a specific chemical exposure at baseline, is it necessary to ...
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19 views
Combination of between and with-in design
TEST 1:
Group 1 consists of 100 men.
Group 2 consists of 100 women.
The distribution of blood pressure is not normal.
The distribution of blood pressure for group 1 is D1.
The distribution of blood ...
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37 views
How to test for differences in 3 related measures assessed pre- & post- treatment on the same sample?
I am designing a study to compare whether one specific treatment improves Quality of life. I am using a convenience sample ($N=20$). I hope to administer three ...
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1answer
32 views
Appropriate Analysis for ordinal variable, repeated 4 times under different conditions, by the same 2 raters
I am doubting myself on which analysis to run for the following:
18 participants were evaluated at 4 time points with different conditions at each time.
They were given scores (on a discrete visual ...
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0answers
17 views
Calculating a correlation across repeated measures
I am looking to test the correlation among variables that are tested at multiple time-points, and am looking to see if there is a way to calculate a correlation coefficient that takes into account the ...
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2answers
83 views
Is a pre-post intervention study with a control group without random assignment quasi-experimental?
I am currently rather confused about the design type for my study.
I am looking at a number of measures pre and post intervention with control group in a community sample. The sample collected was ...
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62 views
Finding post-hoc power of a repeated measures ANOVA using G*Power (Am I entering the right parameters?)
I would like to report the power observed with my mixed model analysis (or repeated measures ANOVA). My experiment followed a completely within subject design with 2 independent factors (two levels ...
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78 views
Help analyzing repeated measures categorical data
This is my first post. I have the following data set-up: I asked 331 subjects about whether or not they would take a drug to enhance the following four domains/abilities: Cognition, Mood, Sex, and ...
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1answer
82 views
Exploratory Factor Analysis Using Data Appended By Group
I am working on an analysis using exploratory factor analysis (EFA) with the common factor model. This question concerns a methodological issue. Any insights from someone who knows about EFA would be ...
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1answer
162 views
Moderation in repeated-measures design?
Context: Both dependent $(Y_1,~Y_2,~Y_3)$ and independent $(X_1,~X_2,~X_3)$ variables were measured repeatedly at three time points, $\text{Time}_1$, $\text{Time}_2$, and $\text{Time}_3$. Moderator ...
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41 views
Repeated measures data
Suppose you have data where you measure a subject at 10 different time points but some subjects are measured at less than 10 time points. Can you still apply standard methods to model observations at ...
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0answers
120 views
Mixed models and normally distributed random effects
I am attempting to analyze some data that includes 10 repeated measurements on 10 different samples. This would normally require using mixed models, and I have attempted to model these using ...
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1answer
52 views
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39 views
Two uneven groups (101 vs 21) measured twice; what repeated measures ANOVA equivalent can help?
I have a question that I have difficulties in answering:
I have two groups of patients tested twice at the same continuous variable.
Group A=104 & GroupB=21.
So two groups, one continuous ...
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48 views
Models with Nested Effects
I am having difficulty understanding nested effects. Suppose 20 people each are assigned to treatment groups A B C and D. Would it be correct to say that Person is nested within treatment group? So ...
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1answer
106 views
How do I set up a single continuous independent variable for a repeated measures linear model?
I'm doing an education study and I'm trying to see the effect of website usage on quiz scores in a class of college students. There were 30 students in the class and they took 10 weekly quizzes over ...
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26 views
2 x 3 Intervention Study Design
I have an intervention that I want to test and I am a little bit "statistically challenged." There will be two groups (treatment and control) over three periods of time (pre-test, post-test, and a ...
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2answers
169 views
Plotting and presenting longitudinal data, options?
Hypothetical Scenario: A few continuous variables, each measured repeatedly at, say 12 time points, each with say, 150 observations. There are small fluctuations from one time point to another (i.e. ...
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74 views
Comparing max/min over several time points against baseline
I have a time-series dataset with repeated measurements (multiple subjects). I have around 100 variables to test. The question is - Is something happen in a time range independently on exact time? For ...
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1answer
83 views
repeated measures factorial design
I have learned about repeated measures ANOVA but is it possible to have a repeated measures factorial design? So if you have factor A with 2 levels and factor B with 2 levels where each combination ...
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0answers
28 views
How can I analyse results from a repeated in repeated measures mixed design in r
I want to investigate performance in a learning test, where my test animals have been submitted to a number of trials within test day over several test days. I want to investigate if there is an ...
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0answers
18 views
Help needed in computing Inter-rater, intra-rater variability
I have been working on a test in which I need to quantify the variability in a process. The process in question involves positioning a number of landmarks on an anatomy. There are two sets of ...
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1answer
87 views
Repeated Measures ANOVA missing values - run separate models?
I am evaluating pre and post test data for 2 groups using repeated measures ANOVA. Given that I am missing a few data cells, the final n is reduced in the analysis. I'd like to know if I can run ...
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10 views
Is dependence of one classification on another a violation of the assumption of independence for ANOVA?
My subjects are mice, swimming in a pool for 60 s. The DV is how much time they spend in each quadrant of the pool. The performance of each subject is independent of every other subject. However, ...
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2answers
53 views
Paired Differences T-tests for Odd number of Observations
Suppose we have $m$ baseline data points and $n$ post-baseline data points where $m < n$. This is for one subject. Is it possible to perform a paired t-test on this data even though $m+n$ is odd? ...
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100 views
Repeated measures ANOVA: Mauchly's test undefined
I'm doing a two-way between-within ANOVA in SPSS. I have two groups with 9 subjects each (so total = 18), and 24 levels of one repeated measure.
I understand why Mauchly's test of Sphericity has no ...
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0answers
31 views
Comparing difference scores between 2 groups over 2 conditions
I am investigating a common discrepancy between male and female self-reports on a survey about sexual experiences. Generally, women report ~2/3 higher rates then men do. I have modified the survey ...
2
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2answers
139 views
Which are the correct sum of squares for repeated measures ? (balanced example)
Below are three ways to fit a MANOVA model in R and to extract ANOVA tables from the fitted model. The design is balanced. All methods give different results.
The data are 5 groups of 4 individuals ...
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1answer
306 views
Post Hoc test for between subject factor in a repeated measures ANOVA in R
I have done an experiment of how different animal species affect nutrient fluxes in sediments. I had a number of experimental units (sediment boxes) to which different animal species were added. I ...
