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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Using the Dunn test to get the CLD grouping for the Skillings-Mack test

I have a set of phenotypic data collected from 9 different assays of a set of different plants. Each plant was assayed at least one time, but each individual assay had a different set of plants. So ...
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In a game with 0.01 chance of survival, there are 100 participants, a specific player survives twice what are the odds?

Sorry ahead if my question is very beginner-ish but I'm confused with this example. Your help is appreciated Let's say we have a survival game where 100 players participate each time and only one of ...
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lme4: glmer() warning messages with count data mixed-effects model and how to proceed with model fit

I have fitted a GLMM with the function glmer of lme4 package. My data consists of a repeated measures count variable, which I am trying to explain with a continuous variable (week) and some ...
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Make a pairwise comparison among sub-groups of a variable

I have a dataset that includes a variable called SoundDirection. The variable contains 6 levels, each one scored in a likert scale from 1 to 5. In the experiment, every participant had to listen to 40 ...
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R: emmeans back-transformation when using a constant value in the response formula

I am fitting a linear mixed model ...
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How are effect sizes calculated following a cellwise residual analysis?

I have used SPSS to create a 2X4 contingency table concerning the relationship between two categorical variables: depression diagnosis and 4 sleep disruptions. I carried out a chi square test of ...
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Post hoc power analysis for multilevel regression analysis

I have a multilevel model with 2 levels (L1 = individuals, at least 710 per country; L2 = countries, 17 total) ...
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Hypothesis test for classification model

I have a model that outputs 0 or 1 for interest/not-interest in a job. I'm doing an A/B/C test comparing two models (treatment groups) and none (control group). ANOVA for hypothesis testing and t-test ...
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Following a post-hoc ANOVA, how do I write the significantly different superscripts?

If my data is as follows: 1 - 6.480 2 - 8.019 3 - 9.110 4 - 10.580 5 - 11.400 6 - 9.733 7 - 9.750 8 - 7.000 On the post hoc ANOVA the average LSD is 2.526, which data sets are significantly different? ...
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How to compare ANOVA results from multiple data sets

I am trying to find out if there is an age-education category difference between people in the number of votes which they use while voting with a multiple vote voting method. Basically, I am trying to ...
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Summaring post hoc differences of means for several groups

I have 5 groups with unequal variances. I used a Welch's ANOVA and then a Games-Howell post-hoc analysis to find the pairs that have significant differences. I have a large number of samples in each ...
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Generalized linear mixed effects in repeated measures analysis

I'm new here and my question might be a bit long. Sorry in advance. I want to analyze two groups of patients in repeated measures, and to investigate whether there is a significant difference over ...
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A post-hoc test for linear regressions with interaction?

I've been looking for an answer for a question (which I thought was rather trivial) for a while now, but can't seem to get the correct solution for it. I'm working on data of blood parameters (e.g. ...
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huge degrees of freedom for post-hoc tests of lmer model using emmeans

I have a trial-wise linear mixed model with a categorial between-subjects factor group (A vs B) and two categorical within-subjects factors itemEmotion (neutral vs. negative) and neuralArea (frontal ...
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Older adults verses Younger adults - RM ANOVA non sig interaction

I am running a 2x4 ANOVA (between: old verses young adults), (within: reward 4 levels). In the overall model I have a significant main effect of reward, and a non significant interaction. I have no ...
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Is it appropriate to remove biologically meaningless pairwise comparisons after Dunn test for a post-hoc(FDR) analysis for multiple comparisons? [duplicate]

I have four individual groups(A, B, C, & D) Differences between the groups are being analyzed by the Kruskal-Wallis test followed by Dunn's test for multiple comparisons (dunnTest command in R). ...
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What post hoc to use after finding significant main effects and simple interactions in a GLMM?

I have a experiment with multiple nominal and ordinal variables of interest ($7\times4\times3\times2$) as well as 3 nominal nuisance variables ($2\times2\times2$). The one outcome variable is binary: ...
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On what conditions of a 2x2 ANOVA is a post-hoc test necessary?

If the point of a post-hoc test is to determine where exactly the variance originates from, then does an ANOVA 2x2 results table, where all of the sources of variation between different groups are ...
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Reporting multiple one-way ANOVAs concisely

I am writing a report on my findings. I have used an ANOVA test on 15 different dependent variables. The dependent variables are execution times of some processes. I considered the variables ...
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Effect size measure for post-hoc tests after nonparametric tests: Alternatives to calculating r from z score?

I've calculated Friedman's tests for my data and want to report an effect size with the individual post-hoc tests that followed on from the statistically significant Friedman's test. I use the formula ...
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Beta regression using categorical variables

I have been asked to do beta-regression for my data. The independent variable is categorical (there are three treatments A, B and C). The dependent variable is the proportion of time an animal is ...
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Next step after ANOVA

The ANOVA test I ran on my dataset resulted in the rejection of the null. What is the way to tell which treatment is significantly different from the others? Should I do a bunch of paired t-tests or ...
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Probing categorical (3 levels) x continuous var with emmeans

I am trying to probe the following significant interaction between Condition (categorical, three levels) and time (continuous) using R emmeans package: Original formula for the model was: ...
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Error in post-hoc analysis on gamlss model with emmeans: "Error in V[idx, idx, drop = FALSE] : subscript out of bounds"

I am utilizing gamlss currently because of its flexibility in specifying 'rarer' data families but run into an error when trying to compare 2-by-2 differences in mu effects for my fixed model factors. ...
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pairwise comparisons, emmeans or by hand

I have an lmer model with one categorical variable and several continuous variables. The results are as follows: ...
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Why are the stated facts about using the Mann-Whitney U test for post-hoc testing after a Kruskal-Wallis test a problem?

I've read here on several threads that using Mann-Whitney U for post-hoc tests are an issue because: the ranks that the pair-wise rank sum tests use are not the ranks used by the Kruskal-Wallis test (...
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For Friedman Test, what are the pros and cons of different post hoc comparison method?

scikit_posthocs lists some post hoc pairwise comparison methods if significant results of the Friedman’s test are obtained. How do I decide which one to use? In my case, the toy dataset ...
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How to do a post-hoc comparison after friedman.test?

An example is as follows: ...
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Testing for statistical significance of the true positive detection rate between different machine learning models

Background Currently I am working on true positive detection for an image analysis problem. I have 4 methods and would like to test which methods differ from each other. Description of Data For each ...
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Explaining a repeated measures factorial experiment with the linear mixed effect models' output instead of running the "classical" ANOVA

I am analysing a database and I am stuck. I would need an help. Data are from a factorial design. Participants (patients and controls) were asked to complete six balance tasks while standing on force ...
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How to perform a post-hoc test on the lmer model when the data is very large

I'm trying to do post hoc for my lmer model. My fixed effects are all continuous variables. I tried the emtrends() function in the 'emmeans' package. ...
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Concept clarification: which pre-test probability to use for the Fagan’s nomogram

I am currently testing the diagnostic accuracy of my predictive model. I hope to visualize my model using Fagan’s nomogram. I want to ask for the pre-test probability in the nomogram, should I plug in ...
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What test/posthoc test for within-subjects, non-parametric ANOVA? Need help with a complicated analysis

Experimental Design: 3 different 'devices', 3 different 'rho' values, 3 different 'lambda' values = 3x3x3 = 27 'blocks' where a block is a combination of 'device', 'rho', and 'lambda' (e.g. "...
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2 votes
1 answer
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Can we report an F statistic on a Robust Linear Model with only Fixed Effects?

I'm estimating a fixed effects model using Linear Regression with the Huber weighting function. I included a boxplot of the data. How do we report an F-value and significance for the entire model like ...
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Confidence interval crosses 0 but statistical significance at p < 0.05 using robust post hoc tests, any explanation?

I have 12 groups so 66 contrasts, though I'm only interested in 6 of them, I'm using the mcppb20() function from Rand Wilcox's WRS package in R. I'm using 5000 bootstrap samples as suggested and 0.2 ...
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ANOVA post-hoc correction question

I am currently analysing data from a recent experiment, in which I will perform a 2 way repeated measures ANOVA (exercise intensity [3 intensities] x time [5 time points]). I have a significant ...
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Four factor anova model effects specification

I am trying to run a four – factor nested ANOVA (Factor B nested under Factor A) in STATISTICA 7. Factor A with a levels, Factor B with b levels, C with c levels, D with d levels, and s subjects per ...
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How to confirm (for reviewers) that possible nuisance variables have not affected my experimental outcome?

We are undergoing review on an auditory perception experiment. We purposely used naturalistic stimuli, which differ in various acoustic features. To deal with this natural variability, we produced 8 ...
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Test the slopes of model with an interaction against the slope of a model without interaction

I would like to compare the slopes obtained from a model containing an interaction with a similar model without an interaction. Here is an example to make my question clearer: Let's say have the ...
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Post-hoc test of two-way permutation ANOVA

I have a 2x2 study design to test the interaction between two drugs, with a single variable outcome. The data are very much non-parametric and it seems that a good alternative to the traditional two-...
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Performing post-hoc tests on a GLM with Gamma distribution

I am analyzing data that is gamma distributed. Hence, an ANVOA was a good choice but a GLM with gamma distribution worked well. To report the data I want to compare all groups to the control treatment ...
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Post-hoc test for PERMANOVA (adonis2) of a single variable (vegan package)

I have a 2x2 study design to test for the interaction between two drugs (i.e. with or without drug1 and/or drug2), with a single continuous outcome for each combination. The data are unbalanced and ...
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2 votes
2 answers
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Which is the most suitable non-parametric test (and post-hoc)for a heavily umbalanced groups (3, 15 and 11 observations)?

I am comparing soil properties among different geological substrates. I have only 3 observations in one category (karst soils), 15 observations in sedimentary terrains and 11 observations in ...
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Post-Hoc test for multiple comparison when there are two control group (cancer research)

I would like to give some context, I have 4 experimental groups: A.- Control ( or tumor free) B.- Control + Drug C.- Tumor D.- Tumor + Drug What would be the correct post hoc test ? My interest is in ...
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How can I use the shared (global) error term in simple main effects for a mixed ANOVA in R?

I'm doing a mixed ANOVA with one within-subjects factor (time) and one between subjects factor (group). The dependent variable is score. When I find an interaction, I want to do simple main effects, i....
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Is the Games-Howell follow-up test appropriate for repeated-measures ANOVA?

In Field's book Discovering Statistics with IBM SPSS, in chapter 15 on Repeated Measures ANOVA, it is written that "When sphericity is definitely not violated, Tukey’s test can be used, but if ...
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Confused by post-hoc comparisons for ANCOVA using either SPSS or R

I ran a two-way ANCOVA with two covariates and would like to run post-hoc comparisons that generate a p-value (the interaction was significant). I'm running into trouble in SPSS, because adding ...
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When applying post-hoc corrections, do you group comparisons?

Say I am using a simple Bonferroni correction. I have two dimensional data, across 4 conditions = 4x2 = 8 hypotheses. Let's say I do 8 t-tests, one for each (condition, dimension) pair. But let's say ...
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4 votes
2 answers
630 views

Which pairwise comparison tests are best to use after the Kruskal-Wallis test (Dunn, Conover-Iman or Steel-Dwass-Critchlow-Fligner test)?

I have 3 sampling sites where I took 3 water samples in each site. I chose to do the Kruskal-Wallis test to find out if there is a significant difference in total nitrogen between the sites. I did not ...
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Is it justified to report standardized residuals from a chi-square test of association as a p-value?

I'm having a discussion with someone about conducting post-hoc analysis after a chi-square test of association. In this case, it's a 4 x 2 contingency table where the four categories (rows) are ...
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