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Questions tagged [post-hoc]

"post-hoc" refers to analyses that are decided upon after the data has been collected, as opposed to "a priori".

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ANOVA finding a main effect prevents inflation of Type I error rate

In the (free) book Understanding Statistics and Experimental Design, section 6.3, they say '...ANOVA offers a second trick. If we rejected the null hypothesis, it is appropriate to compare pairs of ...
Quinn Culver's user avatar
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12 views

Post-hoc tests for repeated measures ANOVA with aligned rank transformed(ART) data

I'm working on a 2x3 factorial design with two within-subject variables and I'd like to test for both main and interaction effects. Since the data is not normally distributed, I've performed an ...
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Correct test for regression with more than two factor levels?

Is it correct to use a "post hoc test" (e.g. a Tukey test) to analyse differences among factor levels in a linear regression or is there another method that is preferred? In my case, I have ...
Picapica's user avatar
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1 answer
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glmer significant and post-hoc test not significant

I ran a glmer model to test the effects of treatment on my response variable ...
GiorgioS's user avatar
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32 views

Post-hoc tests for a Generalized Linear Mixed Effects Model

This question is linked to this one. I wanted to know whether the application of a treatment would have a significant effect on the proportion between healthy leaves and infected leaves. I have the ...
GiorgioS's user avatar
0 votes
1 answer
141 views

Reviewer wants "post-hoc" power analysis for a mixed effect model [closed]

I have a multilevel model in a mixed design: mod <- lmer(score ~ group*time + (1|id), data = df, REML = FALSE) Where score is continuous variable, group is a ...
Imhotep's user avatar
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1 answer
17 views

Is it possible to belong to two different homogenous groups for tukey-HSD

I want to start by saying I'm a beginner in statistical analysis, I'm learning for my thesis and I'm using the TIBCO Statistica software. So basically what I did is cluster analysis and got 4 ...
TiredStudent's user avatar
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Can I use games-howell post hoc for specific pairwise comparisons?

I will provide more context: My initial intent was conducting a one-way ANOVA and then follow up with planned comparisons (contrasts). Sadly, the homogeneity of variances assumption was violated, and ...
Guy's user avatar
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Non-parametric tatistical test and post hoc for two-way layout with longitudinal data?

I have questions about the approach in statistics that I'm taking for my experiment. However, I do not have a good understanding of statistics, so I opted to add more information than less. My ...
DangIt's user avatar
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2 votes
0 answers
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untrustworthy p values? emtrends following lmms with fixed effects of different levels of repetition

Edited to clarify further 23/04/24: I have a fairly complex linear mixed effect model in R and I believe that there are issues to do with repeated data when running my post hoc tests. The model ...
Hannah Gibbs's user avatar
2 votes
2 answers
67 views

Is the post-hoc observed effect size redundant with the p-value, just like post-hoc observed power is?

Assume for simplicity sake that we are running a 2-sample t-test on 2 normally distributed populations, from which we collect 2 i.i.d samples. (for a start; we can expand later to more complex cases). ...
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3 votes
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multiplicity-adjustment w/ unequal variance & pre-planned vs post hoc

The (only) answer to this question says If the variability of the data in each category of your factor is non-constant, that would invalidate ... your multiplicity-adjusted post-hoc p-values. Why ...
Quinn Culver's user avatar
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Appropriate way to correct for multiple hypotheses with multiple one-way ANOVAs and Tukey's post-hoc

I have a dataset with four groups and 14 different dependent variables. Based on the answer given here, I think the best approach for my analytical question is to perform multiple one-way ANOVAs, ...
Geoff's user avatar
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1 vote
0 answers
31 views

Non-parametric ANCOVA post hoc test

I am doing a non-parametric ANCOVA (my residuals are not normally distributed and transformation did not help), I have been using the sm.ancova function from the sm package in R. Now I want to do a ...
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Is correction for multiple comparisons necessary in this instance (single variable)?

Coming here from a more analytical chemistry background, but I figured I would run my current thoughts here before committing to anything after looking around for a bit. I'm used to always using ...
toasty53's user avatar
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Full Factorial Designs and Honest Tukey

I am trying to analyze the data of a 2x2x2x2 full factorial design experiment. (It wasn't my idea.) Mercifully, we have plenty of data per run, each run has the same amount of data, and normality and ...
Anonymous's user avatar
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nlme prediction differs largely from a 3 way interaction model to its post-hoc follow up

I'm trying to predict that speed at which people complete a walking test, where they perform this test for multiple trials and overall increase their performance on each trial. They perform as many ...
user410044's user avatar
1 vote
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Strange results using Dunn's test [closed]

I am receiving a result that seems very counter-intuitive using the Dunn's test. My data is illustrated in the plot below. I have 5 groups (labelled muscle1a, muscle1b, muscle2, muscle3 and muscle4). ...
HanLisb's user avatar
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1 vote
1 answer
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How to set contrasts for contrast in post-hoc comparison of linear mixed effect model in R?

i am new in R and studying statistical analysis for experiments, please help me~ I have 3 age groups (Y/HO/LO) and 2 conditions (Related/Unrelated). I am running a linear regression model on RT (...
Yun's user avatar
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0 answers
21 views

How to do ANOVA/post-hoc analysis when 'control' is used to normalise the data?

I am analysing the transportation rate for a number of different mutants in a particular transportation system. I want to know how I can perform statistical tests on this data in a valid way, given ...
Rachel Jones's user avatar
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Post-hoc tests of interaction for a negative binomial regression with survey weights?

I ran a negative binomial regression with survey weights using the R package survey and the function svyglm() and observed a ...
Chernoff's user avatar
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0 answers
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Post hoc power for multiple logistic regression

I have data frame named "finalend", I conducted multiple logistic regression model named "model" with all predictors as categorical or binomial variables and "TestAnxiety"...
NEA's user avatar
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0 answers
18 views

Can I 'double' dip into a baseline to both reduce variance, and use it as a level of my with factor of time?

I have a bit of a situation I would like some advice on. I'm currently running a human subjects study where I have two groups (group 1 and group 2), and three time points. Each subject performs a ...
JBugg's user avatar
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23 views

Identifying the type of missing data and the post hoc test that can be carried out for Skillings Mack test

I have a non-normal paired sample dataset. Each row represents a dog that has been tested for an experiment. Each dog was provided with three cues (treatments): 5s cue (aka only face cue), vocalone (...
Rohan Sarkar's user avatar
1 vote
0 answers
28 views

What counts as pseudo-replication?

I'm interested in adding a new factor to my data set (to model against my response), but I need help thinking through if doing so would introduce pseudo-replication, or other problems as well. The way ...
Nate's user avatar
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1 vote
0 answers
30 views

Assumptions and validity of post-hoc pairwise comparisons of GLMs

How does packages for pairwise comparisons such as multcomp's glht(mcp) and emmeans pairs() maintain validity in cases of ...
arebru's user avatar
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2 votes
0 answers
119 views

Post hoc after a 2xN chi-squared test

I have two groups of people, and I want to determine if there's a significant difference based on their language. My data consist of word frequencies (how many times a person sayed a given word in a ...
ALESSANDRO GNUTTI's user avatar
1 vote
0 answers
33 views

Statistical Comparison of Continuous Outcomes Across Groups with Identical Observations

Cross Validated community, I am working with a dataset of restaurants that have been classified by both Michelin and Rafaelo rating systems. Specifically, Michelin has categorized restaurants into A, ...
insan's user avatar
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1 vote
0 answers
115 views

Why do Welch's t-test results differ from Welch's ANOVA post-hoc tests?

I have data on elevation between three different berry types in Python (Raspberry, Sunberry, ...
Thomas's user avatar
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1 vote
0 answers
14 views

Alternative to Nemenyi posthoc test that can use variance

I am applying statistical tests from paper "Statistical Comparisons of Classifiers over Multiple Data Sets" J. Demsar (link) in my own work. However, variance is pretty important, since ...
qalis's user avatar
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1 vote
0 answers
34 views

How to test the effects of multiple factors on classification accuracy? (Incomplete, unbalanced data set.)

I have a data set of classification results that are binary (correct prediction or false prediction). Each entry stems from one of multiple models and contains a few more factors: ...
Manuel Popp's user avatar
1 vote
0 answers
47 views

Kruskal wallis and posthoc test verification?

I am trying to run a kruskal-wallis test on my dataset. Dataset is given below: ...
Betelgeuse's user avatar
1 vote
1 answer
47 views

Compute ANOVA F if you only know post-hoc results

It's not uncommon to read a scientific article in which the authors perform an ANOVA followed by post-hoc t-tests, but don't report the results of the ANOVA at all, and instead skip straight into the ...
David B's user avatar
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1 vote
1 answer
153 views

Post-hoc test for mixed effect model adjusting p-values

We are performing post-hoc test(s) on a mixed effects model for repeated measurements in R (nmle and emmeans package). For ...
JJR's user avatar
  • 157
0 votes
1 answer
42 views

Multiple comparisions between sexes within years ANOVA or t-tests? Tukey posthoc? Bonferroni?

I am conducting a genetic analysis comparing Fst and relatedness coefficient values between male and female animals across years from 2013-2019. Each year is divided into quarters, so I have a total ...
Kyle Finn's user avatar
1 vote
1 answer
29 views

How can I interpret non-significance in models built with subsetted data?

I am working on revisions, and it was requested that I re-run my models separately for males and females. When I do this, I lose statistical significance in some tests in females but not in males, but ...
HarD's user avatar
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8 votes
3 answers
1k views

Non-significant results when running Kruskal-Wallis, significant results when running Dwass-Steel-Critchlow-Flinger pairwise comparisons

I am writing my Master's thesis on adult's performance on cognitive and linguistic measures. I have four age groups and am investigating if there is an age difference in the performance on summarized ...
Samplename1's user avatar
0 votes
0 answers
47 views

Post-hoc test for Bayesian ANOVA in R

I set up an ANOVA to test for a 2-way interaction. However, for my hypothesis I would need to test whether the levels A and B of facor 1 are different for each level of factor 2. In a frequentist ...
rbeginner's user avatar
0 votes
0 answers
39 views

How do I obtain a one-tailed p-value for Games-Howell's test (as calculated by most R functions)?

I am trying to understand: 1 - why p-value is calculated as it is in Games Howell test, and 2 - how to modify an R function to obtain a one-sided (alternative: greater) p-value for the test When it ...
Sephirothmn's user avatar
2 votes
1 answer
87 views

Bonferroni Post-hoc after normality test following a glm()

Experiment Design Mice belonging to knock-out ($n=7$) and wild-type ($n=6$) had their food intake recorded per hour across a 24 hour period. Within this 24 hour period, the first 12 hours is labelled ...
JLit98's user avatar
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0 votes
0 answers
66 views

Multiple regressions with each factor level as contrast coding

I've determined there is a difference in factor levels on a dependent variable. I'd now like to determine which level differs from other levels. I know I can use contrast coding, specifically ...
Brian Syzdek's user avatar
0 votes
0 answers
61 views

Post-hoc test for a glmer model fitting a paired sample, repeated measures, poison distribution

I have paired sample dataset where the same sample received Treatment('Drug A','Placebo') on different days and i am comparing the effects of my response variable (i.e. Left_Pokes) per minute (i.e. ...
JLit98's user avatar
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0 votes
0 answers
57 views

Significance in 3x3 crosstab including low values and high N

I am conducting a study of 126 organizations. Each organization has one or more registered domain names. Each domain name needs to conform with specific cybersecurity requirements. Some ...
possum's user avatar
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1 vote
2 answers
350 views

SIgnificant ANOVA but not significant post hoc ... what can I do?

I am analyzing some IHC data on the density of cells in two brain regions(factor 1) in two closely related species(factor 2). My data is composed of an n of 6 for each species and is not normally ...
Daniel Corrales's user avatar
1 vote
1 answer
367 views

Would a post hoc power analysis be used for a retrospective chart review and how would this be done?

I'm a novice in research and wondering if I need to calculate power to determine my sample size. My study is about collecting data from all patients that presented to a clinic for a period of 6 months....
Raji's user avatar
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1 vote
0 answers
76 views

Compare quadratic coefficients between group levels from mixed effects model?

I'm hoping I can find some advice on this question. I have repeated measures of an outcome variable yvar where the trend over ...
Jem Arnold's user avatar
0 votes
0 answers
53 views

3 way interaction in linear mixed model with 2 continous and 1 categorical predictors

I want to know if the relationship between x (continuous independent variable) and y (continuous dependent variable) is influenced by gender (binary variable) AND stronger for those participants who ...
Mika2019's user avatar
1 vote
1 answer
86 views

Is there any post-hoc test for multiple comparisons after conducting the Friedman test by two group using a preference ranking questionnaires?

I have this dataframe: group1<- matrix(c(rep(1,5),rep(2,5),rep(3,5),rep(4,5)), ncol=4) group2<- matrix(c(rep(4,5),rep(3,5),rep(2,5),rep(1,5)), ncol=4) I ...
user avatar
3 votes
1 answer
389 views

How to interpret a sensitivity analysis from G*Power for a repeated measures, within factors ANOVA

I am trying to conduct a sensitivity power analysis for a (2x2) ANOVA. The participants all received trials based on color or shape, and items could be either old or new. In G*Power I have the ...
gert's user avatar
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3 votes
1 answer
219 views

Discrepancy between the results of the ANOVA and the post-hoc test: How should be such results interpreted and presented?

It is possible to find discrepancies between the results of ANOVA and post-hoc tests. The results of post-hoc tests are valid (with the exception of the Fisher LSD test) even if the overall P value ...
benjamin jarcuska's user avatar

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