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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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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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0answers
15 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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0answers
9 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
25 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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16 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
34 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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7 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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18 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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9 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
21 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
36 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
26 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
21 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
34 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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0answers
30 views

How run run followup (post-hoc) tests for multiple Chi-square tests

I have been looking around on the net looking for the best way to do a post-hoc analysis for multi factor significant chi-square test, with no success. I have a data-set of patients with different ...
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1answer
33 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
32 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
84 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
78 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
11 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
46 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
44 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
64 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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How to Control the Type-1 Error Rate for T-Tests Used to Understand Sig. Interaction Effects

Basically, I ran a repeated measures ANOVA between groups R and D with one within-subjects factor with 2 levels. A significant interaction was found. To understand what was driving the interaction I ...
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1answer
88 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
94 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
204 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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0answers
19 views

Post-hoc analysis on data, if three-way ANOVA is showing interaction

I have a data set with three independent variables. After applying three way ANOVA, I see significant three-way as well as two-way interactions. Will it still be acceptable if I apply some post-hoc ...
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1answer
53 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 ...
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19 views

Is it legitimate to design a one-way ANOVA with following post hoc test in mind?

Is it legitimate to design an experiment where I conduct a one-way ANOVA and test for group differences with a post-hoc test? I read on researchgate, that it's bad practice to do so and post-hoc ...
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1answer
185 views

Report GLM and Posthoc with emmeans in APA format

This is the results of my anova(glm()) and the post-hoc analyses emmeans() :       ...
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1answer
36 views

Multiple testing adjustments in posthoc.quade.test

In R, posthoc.quade.test (package PMCMR) or quadeAllPairsTest (the new variant, PMCMRplus) are posthoc tests for Quade test and offer the option for adjustments (i.a. Holm, BH etc.). In my previous ...
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1answer
87 views

2-way ANOVA multiple comparisons question

My question is about a 2-way ANOVA for an experiment. For simplicity let's say I'm using 3 methods to stimulate cells at 3 different time points, and I want to look at a resulting output variable. ...
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0answers
19 views

Post-hoc testing for mixed ANOVA with lme

I'm carrying out a mixed 2 (between: native, non-native) x 3 (within: offer type) analysis, however, I've been struggling to get the post-hoc test to work. I've tried the following: Lme.mod <- ...
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1answer
23 views

ANOVA: Non-significant main effect with significant post-hoc test?

I need some help in interpreting a situation in a 4-way ANOVA where a given factor does not show up as significant in the omnibus model, but the post-hoc comparison between categories of that variable ...
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1answer
71 views

Are the results of my paired tests false positive?

I am dealing with a strange situation which I hope you can come up with a solution. I have 3 pared group(n=7 for each) which I tried to see if they are significantly difference and if so, in which ...
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0answers
33 views

Post hoc analysis survival data and maximum lifespan survival correction

I every body! Before to present my problem I apologize that I creates the same topic on the forum stackoverflow, but I think the best place for my question was here. I'm a PhD student and I'm ...
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1answer
62 views

Test statistic for follow up procedure (stepwise step down) of Kruskal Wallis

When conducting a Kruskall Wallis test, it is possible to follow up the procedure with a post hoc test, looking for homogeneous subsets. My question is which statistic is used to perform this ...
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18 views

Significance testing with ordinal and continuous variables

I have a continuous normally distributed dependent variable (-1:1) and an ordinal independent variable (Low, Med, High). I want to test whether there is a difference between groups. I could use an ...
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1answer
66 views

Is dunn.test for two samples equivalent to wilcox.test?

I know that dunn.test is generally used as a post hoc after Kruskall Wallis to see which groups are different, but to generalize the function I am writing, I was wondering if when only using two ...
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2answers
290 views

Post hoc test for Friedman test

I am running a Friedman test for my non-Gaussian data, on MATLAB. However, I am confused about the post hoc test to choose. Two concerns: (1) MATLAB's multcompare ...
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1answer
142 views

Post-hoc testing in emmeans for mixed-effects models (lme4) with interactions in R

I have a linear mixed effects model (say AxBxC), where all of the 2-way interactions are significant but the 3 way interaction is not, and I want to perform post hoc contrasts on the 2 way ...
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1answer
46 views

F to report woth Duncan Post hoc?

I am currently writing the session results in a paper. I performed a simple repeated measures anova with two within factors and I got a significant interaction. I perform my Duncan Post Hoc, and I ...
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0answers
10 views

Pre-Post control impact analysis with multiple observations

I have pre-post data on a test being done on 2 cities (one is a control-one is the treatment). I need to analyse this to check if there is a significant change observed in the treatment city. Data is ...
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0answers
70 views

adjusted p-values for post-hoc tests?

I'm analysing about 20 lab-results of three different groups either with ANOVA, Kruskal–Wallis test or chi-squared. I correct the resulting p-values for multiple testing using the Benjamini/Hochberg ...
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0answers
95 views

Bootstrapped post-hoc analyses for mixed effects models

I am using Linear Mixed Effects modelling (LMM) to test the effect of a single predictor 'Age' (a 4 level factor: "-1", "1", "3", or "8") on a logit-transformed response variable (percentage herbivory)...
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0answers
28 views

chi sq post hoc analysis

I ran a chisq.test for group (3 levels) and Age (3 levels) which came back as significant. I ...
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0answers
37 views

Difference between glht and anova for lmer post-hoc?

Following from the useful answer at How to perform post-hoc test on lmer model?, why am I getting massively different p-values when comparing anova() main effect to the glht() post-hocs for a 2-level ...
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2answers
280 views

Report p-values from model fitting or glht?

I am running a mixed model to compare two groups in a repeated measures design. The model is very simple: ...
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1answer
40 views

dropping non-significant interaction terms

I have a simple design with two factors (each with two levels) and their interaction term. I am analyzing it with mixed models. The interaction term is not significant. Do I need to fit another model ...