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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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Post hoc for Levene test

I have a problem regarding my data analysis. One of my hypothesis is basically that my groups will differ in terms of spread of the scores, indicating that there would be a difference in extremity ...
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14 views

Dissertation- how to conduct post hoc on a four-way ANOVA

I am currently in the end stage of writing up my dissertation. I have conducted 4 four way ANOVA's (between groups)- example below 1) the effect of assessment preference (2 levels), somatic group (2 ...
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Is it appropriate to use estimated marginal means when model estimates are not significant but data is unbalanced?

Is it appropriate to use estimated marginal means when estimates (either interaction or main effects) are not significant but the data is unbalanced? I've come across variations of this question on ...
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38 views

Is it okay to do ANOVA on group that is compared with itself and the rest?

I have 4 clusters that is obtained from clustering i.e. Group A, Group B, Group C, and ...
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9 views

Statistical Power alternatives for post-hoc analysis

I am reading about Power and how it is misleading/uninformative to calculate a post-hoc "observed power" of a study. I would still like, after reading a study, to be able to judge its ability to have ...
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36 views

Understanding, reporting and post hoc testing a 2x2 Mixed ANOVA

I one dependent variable, one between groups independent variable (intervention vs. control) and one within groups independent variable (time1 vs time2) so I am using a 2x2 mixed ANOVA. These are my ...
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7 views

How do you run a moderation analysis and post-hoc in Chi square in spss?

How to test for an interaction in Chi-square? Is it also possible to then test for a further interaction in one of the groups? E.g. I test for an interaction in a whole dataset, then split data (?) ...
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23 views

Strange Tukey Output

I'm using HSD.test in package Agricolae to run a Tukey PostHoc test on heavy metals concentrations in otter livers and kidneys. I'm looking at differences between region, river basin, and age class. ...
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42 views

PostHoc Tests after two way anova in R [closed]

I have a data table with 2 explanatory variables: Noise, with 2 levels ("Exposed", "Unexposed") Voltage, with 9 levels The dependent variable is Delta Cm So, after checking Normality and variance ...
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33 views

R: Interpreting the emmeans' t-tests [duplicate]

Since the df are different between t-tests and emmeans ones (cf. https://stats.stackexchange.com/a/369671/217618), how then should I interpreted the results?
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30 views

Planned Contrasts in Mixed models: group with 3 levels

This analysis is based on data from https://stats.idre.ucla.edu/r/seminars/repeated-measures-analysis-with-r/ with some modifications. Pulse measurements were made at 3 time points (1,2,3) for study ...
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1answer
24 views

Post hoc test for chi-squared with given (unequal) probabilities

I am conducting a chi-squared test to see whether the categories survey respondents mention match the distribution of categories in the population. This test is significant, but I am wondering how to ...
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1answer
45 views

Which statistical test for my data?

(EDIT: question simplified) This is a basic question, since I am new to data analysis and statistics. I am carrying out a 2X3 factorial survey where participants are presented with a series of ...
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20 views

Is there a quick way to check the significance for each category of a predictor?

I ran a chi-square test of independence on this data set. ...
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42 views

Possible to extend Gelman & Carlin's “Beyond Power Calculations” when significance not obtained?

I have recently been spending time trying to understand the content and extent/limitations of this paper: "Beyond Power Calculations: Assessing Type S (Sign) and Type M (Magnitude) Errors" by Gelman ...
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1answer
37 views

Testing group means = 0 for multiple factors

I have a dataset that I am analyzing in R. In this data set a value of 0 is meaningful. Therefore, I would like to compare each group mean to 0 rather than comparing them to each other as is ...
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1answer
51 views

Biostats two way anova in R boxplot visualisation

I am having a problem analyzing some data from a recent experiment in R. The experiment was balanced with 5 replicates in each group. It included two factors (plant type and leaf age) with 15 ...
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49 views

One-tailed Conover-Iman test?

I'm new to non-parametric statistics and want to do a post hoc analysis of some data after a Kruskal-Wallis test. I am using the implementation of the Conover-Iman test available in the scikit-...
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44 views

Kruskal Wallis test or Friedman for multiple preselected unmatched pairs

I am unsure whether I should use Kruskal Wallis test or Friedman's test in the following case, where I am required to use a non-parametric test while compensating for multiple comparison with a post ...
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Test statistics of LMM with significant covariate interaction

When reporting on the LMM that I fitted to my data with R, I was asked to include the test statistics (df and others). But I have no idea where to extract them from, I don't see them in the summary as ...
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0answers
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How to compute the average aligned ranks of variables from Friedman's test [closed]

In the paper EUSBoost: Enhancing ensembles for highly imbalanced data-sets by evolutionary undersampling, in figure 2 and 3, the average aligned ranks of methods being compared are plotted. Can ...
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14 views

Post hoc for random effects in mixed effects modelling

Can we carry out a post hoc test like (Tukey, using mult-comp) for "glmer" models for the random effects? My response variable is binomial and there are three levels in the random effect variable. ...
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0answers
22 views

Three way interactions for generalized linear mixed effects model and interpretation of post hoc comparisons

The data I am working on has three categorical variables and one continuous variable. I am using a generalized mixed effects model across four time points before and after administering a drug. The ...
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1answer
33 views

ANOVA with two repeated measures/within subjects factors

We are working on a BOLD fMRI study with a visual stimulation block design. Participants get to see 4 visual stimuli categories in blocks. Each participant belongs to one out of three "experimental" ...
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32 views

R Mixed-Effect Models for 2-way Repeated Measures Design with more than 2-levels in each factor

Background: I am running an experiment with the following parameters. Design: 2-way Repeated Measures Design (as of right now there are NO between-group/grouping variables Dependent Variable: A ...
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22 views

Post hoc for wilcoxon multiple tests

I have a database of brain MRI acquisitions of 20 subjects at two time points. I have elaborated the signal with multiple models. For each model, I have estimated 4-6 parameters maps. At the moment I ...
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56 views

Three Factor Multiple Comparison Post-Hoc Test for Levene's Test

My research question is to find out whether or not my samples are exhibiting any significant differences in their variance in response to three possible treatments. Here are my possible groups: ...
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1answer
30 views

significant $\chi^2$, breakdown shows nothing interesting

Someone I know told me that he had performed $\chi^2$ test of independence with Yates's correction on a $2\times n$ contingency table, seen that $p\lt10\%$ (good enough for his purposes), and ...
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32 views

glmer post hoc test at each time point

I have a question about post hoc tests for glmer. I haven't been able to find a solution on this site or in the documentation. My experiment looks at repeated measures of flower counts (Total) across ...
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0answers
37 views

Alternative hypotheses when conducting pairwise comparisons

When conducting pairwise comparisons, what restrictions are there on the alternative hypotheses? That is to say, is it okay if some tests are two tailed while others are one tailed?
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0answers
18 views

How to interpret non-significant post hoc tests with a significant interaction in 2 way mixed ANOVA?

I've got a significant interaction and a significant main effect in my 2 (within groups)*3(between groups containing a control group) 2-way mixed ANOVA and running independent t-tests to compare each ...
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0answers
55 views

Multivariate $t$ ('mvt') - adjustment in emmeans in R

I am doing post-hoc comparisons of contrasts based on linear mixed models I built in R. I am using the emmeans package for the comparisons. One of the default ...
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0answers
28 views

how/what post-hoc when covariate is significant in MANOVA?

I am running MANOVA with group (patient vs hc) and covariates (age (interval), gender (categorical), handedness (categorical)) on a number (3-8) variables (metabolites; interval). groupmembership ...
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1answer
29 views

Post-hoc comparison using lsmeans paired vs unpaired

I am doing a linear mixed model in R (lmer) to investigate the difference in activity levels (AL) between two disease groups and two kinds of therapy. Additionally, it is repeated measures data, each ...
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1answer
39 views

Correcting for multiple post hoc tests in factorial ANOVA

I have done a two-way repeated-measures ANOVA with factor A having 3 levels and factor B having 5 levels. I am doing post hoc comparisons between all 3 levels of factor A within each of the 5 levels ...
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0answers
115 views

ANOVA with post hoc for non-normal data with unequal variance

I have 200-some variables with 25,000 observations in each of 4 categories. For each variable individually, I need to identify where we have variability between categories. Therefore, I need an ...
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1answer
29 views

ANOVA Test Necessity

I have a question which may seem very simple to someone with more experience in statistics. I have performed a two-factor ANOVA test, without replication, in order to test if there is a significant ...
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1answer
44 views

Post-hoc corrections for multiple t-tests

I am comparing two groups (young vs. old adults) for differences in 5 brain regions (size) with independent t-tests. I also compare performance on three different aspects of a task with independent t-...
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1answer
73 views

Significant Fisher's exact test, post hoc analysis for subgroup comparisons?

I'm analysing 2 groups of patients with 2 different DISEASE_STAGES: MILD disease and MODERATE disease, as defined by a complex clinical diagnosis. The sample size is relatively small: a total of 80 ...
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1answer
67 views

Interpreting contrasts for non-significant interaction in a linear mixed model

I am building a Linear Mixed Effects Model to investigate how activity levels (AL) change between two different types of therapies (TherapyA vs. TherapyB) and how different covariates influence the AL ...
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1answer
157 views

Post-hoc test for binomial GLM with some cases having probabilities of 1

I am studying the effect of plant survival on location and genotype. I fitted a binomial GLM and conducted a post-hoc test after significant interaction using the ...
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1answer
166 views

Correcting for multiple pairwise comparisons with GAM objects {mgcv} in R

My question concerns pairwise comparisons of factor levels in a gam object. I have a dataframe, df, containing reaction time data (in ms) to stimuli varying in ...
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0answers
19 views

How would someone name a “kind of” post hoc power analysis using a priori mean difference estimates?

Imagine a researcher conducted an experiment and tested an hypothesis using a two independent samples approach. It was the first experiment of this kind, so the researcher had no idea about a possible ...
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1answer
72 views

Adjusting p-values for multiple ANOVAs

I am performing multiple (around 40) multi-way ANOVAs on a dataset, one for each outcome variable. There are three factors involved: cohort, pre/post, and tissue type. For each outcome variable, I ...
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1answer
129 views

Which is right to perform a Tukey post hoc in R? [closed]

I know 3 ways to perform a Tukey post-hoc test in R and the results are a little different. Initially, I performed a two-way anova ...
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1answer
166 views

How to obtain the results of the Nemenyi post-hoc test in a table showing grouped pairs?

I performed a Friedman's test, which showed that there are differences among my treatments. Thus, I choose to perform the Nemenyi's post-hoc test in order to infer which treatments statistically ...
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1answer
242 views

Confidence intervals for emmeans estimates after multilevel binary logistic regression

I ran a multilevel binary logistic regression / generalized linear mixed-effects model in R, and then ran the following code to get post-hoc tests for a significant A x B interaction where A is a ...
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1answer
297 views

How are the degrees of freedom in the emmeans package calculated? - R

Let us look at some sample data for 5 hypothetical subjects. ...
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1answer
579 views

Interpreting the standard error from emmeans - R

I am using the emmeans package to run post-hoc analysis on linear mixed models. The results provide what I would expect except for the standard error. I run the ...
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1answer
61 views

Is LMM (lme4) the right way to go? [closed]

I do realize that there are already some questions about the p-values in lme4 and the nested effects but I've got a somehow specific case and failed to find anything that applies to this. I have ...