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 with single measurements

I have the following situation: General practitionar (gp), patient (pat) and consultation (cons). Each gp has several patient and each patient can have 1 and more consultations with a specific ...
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34 views

Reporting results of linear mixed-effects model

Linear mixed-effects models aren't commonly used in my corner of biology, and I need to report the statistical test I used in a paper I'm trying to write. I know that awareness of multilevel modeling ...
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1answer
33 views

Interpreting a significant 2-way interaction with post-hoc tests

I'm analyzing reaction time data from a repeated measures ANOVA with the following design: Factor 1 (between-group): GROUP (controls, clinical) Factor 2 ...
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1answer
49 views

Mann-Whitney test

I am carrying out a study in which I have $3$ groups $n= 2$, $n= 5$, $n=17$. Each group has a different inner ear abnormality, following the fitting of an ear implant I have measured their speech ...
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13 views

Pre-stimulus baseline removal in R

I have the following scenario: trials were conducted where participants were exposed to multiple stimuli during the course of a trial a specific physiological response was continuously recorded ...
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10 views

Repeated Measures Factorial, I think - help?

I have complete data set that fits nicely into excel. One factor is rows (R). The other factor is columns (C). Another factor is related to the analysis of those (F3)... So my experimental design ...
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16 views

Testing contrast between low/high and high/low

I'm trying to understand the results published in Sagristano, Trope, and Liberman (2002). Specifically, I don't understand what analysis produced the result highlighted in the screenshot below. The ...
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11 views

Proportional data with multiple responses

I am trying to analyze a data set in which the response variable is a proportion that can range from 0-1 (inclusive). This response was measured from the same individuals under four different ...
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11 views

Why does “repeated measures” not appear under “analyze - glm” menu in SPSS? [migrated]

This is my first time using SPSS for doing within-subjects ANOVA. Every tutorial I see tells me that I should go to analyze -> General Linear Model -> Repeated Measures. The problem is that under ...
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12 views

repeated measures design between subjects with non normal and small N

I’m examining the effects of a parent-delivered reading intervention on 11 child outcome variables at 3 different time points (pre, post-intervention and follow-up) with a control group. Total sample ...
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8 views

Randomized block design for repeated trials

Suppose I measure reaction time of 4 students, initially before any treatment, then after treatment 1, and finally after treatment 2. (Note all treatments will eventually be applied to all students.) ...
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7 views

Methods for analyzing pre/post test data [duplicate]

What methods of analysis are utilized for pre/post test data when outcome are knowledge scores? In addition what methods of analysis would be used for Likert behavioral score data?
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12 views

Comparing groups using SPSS

I have a dataset with 2 measures that were tested over 30 time points. I have a two groups of people who have both measures at all 30 time points. How do I compare the groups using SPSS?
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12 views

Within Subject ANOVA?

I want to study effect of three factors (Size, Stress and distortion) on readability of graphs. Each factor has two level of difficulties such as easy and hard. Every time I will fix two factors and ...
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12 views

Moderation using ANCOVA

I am performing a repeated measures ANCOVA with Mood Scores as the dependent variable, Image Condition as the independent ...
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21 views

Can I use a paired-samples t-test when the 2 groups that I compare have different numbers of data points?

I want to compare the effect of a drug (immunomodulator) on antibody levels in a group of patients $(n=18)$. Blood samples were taken pre- and post-treatment in each patient and the means of antibody ...
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1answer
63 views

How do I “nest” data in a mixed-effects model? and MANY related questions about mixed effects models!

I treated 80 people with drug X and 80 with drug Y. I presented the drugs to them in groups of 10 (meow groups). The drug was consumed for 15 weeks. They reported the severity of their headaches (from ...
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48 views

NEED ANOVA HELP ASAP!

I have been looking at my stats results for 4 days now and I cannot figure out how to interpret the results. I conducted a within subjects experiment in which participants rated 4 neutral symbols on ...
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1answer
77 views

Multiple measurements per trial in R

Suppose I wish to assess reaction time of individuals before and after treatment, using R code. Now to analyse the results if I had additional treatments, I could use repeated measurements ANOVA in ...
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19 views

Chi-square and repeated measure

I have a survey of 20 questions; answers are given on the 5-point Likert scale. Goal: to understand whether the answer on the first question affects answers on other questions. Normally speaking I ...
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31 views

repeated measures ANOVA with covariate

I conducted a repeated measures ANOVA and added a continuous covariate. Now there is a significant main effect of that continuous covariate. If I report that main effect I need to say something about ...
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19 views

How Can I Simulate Repeated Significance Testing in R

I work in marketing, frequently running A/B tests on websites to determine which variation is best to serve to site visitors. I would like to be able to run a simulation that highlights the perils of ...
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15 views

Linear Mixed Models with variable time points in SPSS

I am analyzing a clinical study measuring patients' symptoms and brain structure sizes over three time points. The "visits" should be at baseline, 3 months and 12 months but they vary considerably and ...
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1answer
60 views

Statistically prove the effectiveness of a treatment using GLM repeated measurements

I have two lots of samples: one is the control lot and the other undergoes some treatment. I did three measurements for the samples: one at the initial time (T1) ...
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1answer
76 views

R gls() vs. SAS proc mixed with interaction: Why does R complain about a singular matrix when SAS does not?

I like to keep analyses all in SAS or all in R when I can help it and lately have been using R more and more, but there's one analysis that I do somewhat routinely that has given me trouble in R. I ...
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13 views

mixed between-within design when covariate-DV relationship is non-linear (quadratic)

My question is about what method to use for a mixed between-within design when the relationship between the covariate and the DV is non-linear (quadratic). My DV is reasoning task score. There are ...
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1answer
37 views

Repeatedly measured, longitudinal and ordinal data

Description of the problem: The effect of a certain treatment is tested as follows: For n subjects, the endpoint is measured three times before and after the treatment is administered, respectively. ...
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35 views

How to compare frequency distributions between 3 groups

I have characterized cells into 6 categories and want to compare the percent distribution of the different categories at 3 time points. Once I figure that out, I actually have additional treatment ...
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1answer
121 views

How to 'normalize' data to account for level at baseline?

In the beginning of an experiment, subjects are required to report on their initial emotions / mood using Questionnaire#1. After the experiment is conducted, the subjects fill another mood ...
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24 views

How to run a power analysis for a repeated measures (all within-subjects) with combined contrasts?

I am looking for a little help on determining the correct way to run a power analysis on a within-subjects repeated measures design (i.e., no between subjects variable) with combined contrasts. ...
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59 views

Which graphs are best suited to visualize multiple pre- and post-test scores between multiple groups?

I have a relatively small sample ($N = 64$) with the following variables: ScoreA_I: continuous pre-test response variable ...
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2answers
70 views

Should the outcome variable be measured at least twice for a longitudinal study?

I am trying to find the association between BMI and onset age of a condition with linear regression model. I have multiple records of BMI measurement. But the outcome variable, onset age of condition, ...
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1answer
46 views

Confidence interval does not include 0, but Wilcoxon test is sgnificant

I've created an error plot with CI 95% to visualize the difference (post test - pre test) between achieved scores. n = 64 Judging from the confidence intervals one could conclude that there's is ...
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53 views

Logistic regression with binary inputs

Is logistic regression an appropriate classifier when the input data are binary? Say we are conducting an experiment where the subject is presented with blue and green circles of varying shades, and ...
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1answer
19 views

Precision of replicated measurements on the same subject

I have developed a technique to count bacteria on a petri dish. Previously these bacteria could not be counted, so there is no reference standerd to compare our measurements with. To show the ...
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2answers
68 views

Determine if two proportions from the same sample are different

Is there a test I can use to compare two proportions from the same sample that are not mutually exclusive? For example, I would like see if the proportion of people that answered "yes" to a ...
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23 views

Simulating data for repeated measures ANOVA

I am currently working on a simulation study in which I compare two methods for analysing data from a repeated measures design. Let's say there are n subjects, and each subject goes through i ...
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1answer
24 views

ANOVA with Repeated Measurements based on randomly assigned repetitions

first of all the basic idea of my experiment: changes/differences of reaction time (RT) after 3 different types of sport (a: no jogging=SP1; b: 10min of jogging=SP2 and c: 30min of jogging=SP3); 36 ...
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55 views

testing differences between levels of a factor in a linear mixed model

I'm trying to wrap my head around using a linear mixed model and appropriate post-hoc tests to determine if there is a significant difference between various treatments in an experiment I inherited. ...
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38 views

2x2x2 repeated measures anova: do I correct for type I error?

I have a 2x2x2 repeated measures design and am trying to decompose a 3-way interaction. As all my factors have 2 levels, I always reach the point that I am doing pairwise comparisons for the simple ...
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31 views

SPSS: How to decompose interactions in repeated measures ANCOVA?

I conducted a study with three categorical within-factors and one continuous personality variable: topic (1,2) x gain loss framing (1,2) x achievement security framing (1,2) x personality I know how ...
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22 views

Repeated measures analysis… or not?

Not sure if dealing with repeated measures analysis...? Measuring X at 3 seasons (summer, winter, spring/fall) during a year – might be high summer/low winter, high winter/low summer, consistently ...
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35 views

Repeated measures logistic regression

I have a dataset that features a binary outcome, a binary predictor, and an unordered factor with 7 levels, and 120 subjects. Each of the 120 subjects were asked a binary question on seven issues, ...
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32 views

I'm stuck: How to 'bin' multiple binary outcome variables and then analyze within subject?

I have what feels like it should be a very easy analysis to work out, but I've been trying for hours and I can't figure it out. I'm using SPSS by the way. I have 10 (5 of each group) different binary ...
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29 views

Does Greenhouse-Geisser correction influence the effect size estimation, the statistical significance treshold, or both of them?

I discussed recently with one of my colleagues about the Greenhouse-Geisser correction for non-sphericity. I told him first that this correction is very conservative and that it would be more ...
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28 views

ANOVA in lmerTest for in-between study with repeated measurements

I have a bit of trouble understanding how to formulate a correct formula in R using the lmerTest-library. Let’s assume there is an 2x2 in-between design with repeated measurements. Those repeated ...
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49 views

Repeated observations on the same unit at the same time point, how to solve xtset repeated time values?

I’m interested in testing the impact of gender on personal selling. I have data on each salespeople’s amount of sales per customer for 22 months from Jan 2002 to Oct 2003 (amount of sales per customer ...
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1answer
50 views

Repeated measures mixed modeling. Why is Time (day, second etc.) a fixed effect?

Let's say I have an experiment where I repeatedly measure something over Time (1:10), say 10 days. Here I simulate some data... ...
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48 views

How to choose a sample size for two group repeated measures anova design given power, alpha, and effect size?

How would I go about computing the sample size for repeated measures ANOVA design, given power, significance and the required effect size (2 groups, I know the mean difference that I want to be able ...
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22 views

Standard error of the mean in a repeated measures study

I am having difficulty figuring out how to calculate the SEM and report it in a table. I have 5 different time periods, and for those time periods 6 different measures of digestibility for each ...