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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8 views

Which post hoc test can I use for LMER with interactions?

I'm struggling to get any post hoc test to work on the following model: no3mod<-lmer(SDBno~Lockdown+Tourist+Age+LockdownTourist+LockdownAge+Tourist*Age+(1|Elephant), data=Prepostlock) anova(no3mod) ...
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Report significance from Tukey HSD

i run a Tukey HSD test inside the R package agricolae and got significant differences between my groups. Now I would like to report that in a figure with the basic ...
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12 views

Multiple Comparison correction for t-tests against chance level in longitudinal analysis

I did a memory test and calculated a "memory index" (in %) in 3 different groups, on a longitudinal scale (4 different time points): I build a mixed model using LmerTest in R, and extracted ...
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How to control the family-wise error rate testing simultaneous hypothesis in two-way Anova?

I guess explaining with an example would be best. Let's say we are researching which type of fertilizer and planting density produces the greatest crop yield in a field experiment. We assign different ...
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Posthoc test after Mixed Anova

I would like to know what kind of posthoc test would be more adequate for time series analysis where after rejecting null hypotesis with Mixed Anova over multiple treatments and a control, i would ...
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Calculate Statistical Power after Pairwise t tests

I am performing post-hoc tests on 4 different data (having equal sd). I am wondering it this makes sense to calculate the power after performing post-hoc tests. The R code is: ...
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421 views

If we shouldn't do post hoc power calculations, are post hoc effect size calculations also invalid?

We have posts on here discussing why post hoc power calculations are flawed. What about post hoc calculations of the effect size that we could catch? That seems logically equivalent. If we are not ...
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post hoc test for a 2x2 mixed design ANOVA in SPSS

I have two independent variables with two levels each: Word type (abstract nouns and concrete nouns), which is my within-subjects variable, and Vividness of visual imagination (high imagers and low ...
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15 views

significance test to compare race-ethnicity among 4 groups

I am trying to figure out the right significance test to determine which of my 4 groups are most (1) non-hispanic white (2) non-hispanic black (3) hispanic or (4) other compared to other groups. In ...
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Simple Contrasts versus Post Hoc Tests in repeated measures, which is preferred?

Planned Simple Contrasts versus Post Hoc Tests in repeated measures, which is preferred? Let's say I have a 10 (Week) x 4 (Group) repeated measures design and conducting a repeated measures ANOVA. My ...
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linear mixed model and post-hoc comparisons

I realised that this is going to be a long post. So I apologise in advance and thank everyone for taking the time. I am performing an MRI study in which I presented visual stimuli of four conditions ...
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What type of analysis to do for Dissertation- EMOTION RECOGNITION

In my study, participants take part in the State Trait Anxiety Inventory (STAI) where they are ranked into high or low trait anxiety groups. Participants are then shown multiple videos of 7 different ...
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What is more powerful – an ANOVA test or post hoc tests?

From answers on this site I have learned that it is possible to get significant results from multiple comparison tests ("post hoc"), even if ANOVA did not yield a significant result. I ...
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26 views

Compare data from two experiments within single logistic regression to determine effect of experimental design?

I've run two studies. Study 1 (N = 112) examines the effects of two variables (A and B), each of which have two levels (a1, a2; b1, b2). For each variable, I'm interested in the effect those different ...
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rm MANCOVA's univariate result does not match the post hoc results. Strange!

I have run a repeated-measures MANCOVA with 2 dependent variables and a 5-level repeated-measures intervention. The multivariate effect of intervention is significant. The univariate effect of ...
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Bayesian GLM/ANOVA in brms — what is the “equivalent” to frequentist post-hoc? Does it matter? [duplicate]

I'm running a one-way Bayesian GLM (in brms in R) between three groups (Class), using a heteroskedasticity adjustment: ...
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123 views

One-way ANOVA followed by Tukey test - confidence intervals

I want to test 3 types of treatments (T1, T2, T3) along with a control/placebo treatment (T4). In order to do so, I'm performing One-Way ANOVA to my data and then proceeding to the Tukey test. ...
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49 views

Understanding Chi Square Post hoc test results

I'm using R and comparing the proportion of Male and Female authors from various academic journals (well, I think I am). Here's a table with my raw data: The code for it: ...
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Multiple comparison correction for Kruskal-Wallis test with multiple dependent variables

I want to compare 3 groups on 10 dependent variables. I plan to use Kruskall-Wallis test with post-hoc comparisons. What kind of correction shoud I use at each step? For one DV it is obvious - I ...
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Post hoc pairwise comparison interpretation?

I have a dataset of the number of social media posts by platform type (row - 3 levels) and account type (column - 5 levels). Using SAS, I've run a Fisher's exact test which has turned out to be ...
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Interpreting post hoc multiple comparisons test?

I have a conducted a Fisher's exact test with Monte Carlo simulation which resulted in a significant p value. My row variable, which is the # of people, has 4 levels (0, 1-50, 51-100, 101-150) and my ...
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100 views

Post hoc test for Fisher's exact test (larger than 2x2)?

I have 2 categorical variables: Var1 - 3 levels, Var2- 5 levels (i.e., table is bigger than 2x2). I'm using SAS, and since I have multiple cells <5, I have run a Fisher's exact test with Monte ...
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How should I proceed when the minimum sample size in an experiment is not reached?

We have an experiment in which the minimum sample size was calculated, but due to the pandemic, data collection had to be terminated earlier, not reaching the minimum size. The statistical analysis ...
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Post hoc analysis for 3x2 cross tab analysis?

Apologies if this is straight forward. Also please note that I am using SPSS and don’t know how to use R/code. I’m a physician doing clinical research. I’m doing an analysis regarding 3 different ...
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post-hoc (Tukey) on adonis (permanova) [closed]

I have a bray-curtis distance matrix and found significant associations on a grouping variable with adonis (permanova) using R package vegan. Now I would like to perfrom a post-hoc test to test ...
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40 views

Contrast post-hoc test on non-significant factor levels

Is it meaningful to interpret the contrast result from a post-hoc test on factor levels that have non-significant coefficients in the fitted mixed model regression? I'm using a contrast test using <...
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P.adjust - different values when using a list vs. individual p-values

I am having some trouble determining the cause of an issue in my R coding. I have a series of 11 p-values, which correcting using the p.adjust function in R with BH corrections. When I create a list ...
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Is there a need to fit lower order ANOVA to find interaction while using emmeans?

I was doing a 4-way mixed anova and observed 2 3-way interaction effects. To investigate further the interaction, the textbook-like plan is to fit a 2-way anova on each level of the third factor of ...
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Interaction term not significant but post-hoc tests are

I'm running a GEE model in SAS with an interaction term between two categorical variables group2 and lbl. Running a joint test, ...
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Correcting for multiple comparisons in simple main effect analyses after signifcant 2-way interaction in SPSS

I ran a 2 x 2 x 8 repeated-measures ANOVA in SPSS and there is a significant interaction of factors A and B (both have two levels). To interpret this interaction, I ran simple main effect analyses ...
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Alternative methods to multiple paired t-tests?

For my project, I want to compare user experience between different assessment formats for 4 different diagnoses groups. I am only interested in the within-group differences and do not want to compare ...
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Does the Nemenyi test include a correction for multiplicity or do I also have to apply a Bonferroni correction?

Does the Nemenyi test includes a correction for multiplicity or do I also have to apply a Bonferroni correction? I appreciate your answer, /Michael
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Post-hoc tests for lmer for two and three-way interactions performing ANOVA type III

In R, I am trying to perform post-hoc tests on a significant three-way interaction involving two 2-level factors (bodymanipulation, soa) and a continuous variable (prosthesis_partofbody). The model I ...
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2 by 2 Mixed ANOVA - To do or not to do post hoc comparisons?

I have a 2 x 2 Mixed ANOVA (2 independent groups assessed at 2 time points). I have a significant interaction, but my question is how can I assess the whether the changes in time over each group are ...
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33 views

post-hoc test that will show interactions

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Post-Hoc Test for a Regression in R

I am currently writing my master thesis and I ran into some troubles. I try to predict the Extraction-Behaviour of participants depending on their own Testosterone-Levels and their believe on how much ...
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41 views

Better to use wald test or likelihood ratio test to make pairwise comparisons after omnibus test in this scenario

I am testing the association between a gene and a binary disease. The gene has many different "versions". These versions are called alleles.I am also including covariates for sex, age, etc. ...
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Is post hoc test needed for stepwise forward confounder/covariate model?

I did a GLMM (corrected for school and administration levels) and analysed the association between food environment and weight status. I corrected for several demographics and other urban variables. ...
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41 views

Running post hoc analysis after running Linear mixed model in R

I have a dataset that has 2 groups ("MICT" & "HIIT") and 3 time points ("pre" & "Trained + AcuteEx" & "Trained"). Below is the code that I ...
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1answer
57 views

PMCMRplus post-hoc Nemenyi's all pairs test ignores alternative?

After a successful Friedman test, I would like to perform post-hoc analysis using the all pairs comparisons Nemenyi's test. Specifically, as I am interested in finding out if the values of some of my ...
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43 views

Post hoc test with heteroscedasticity

I ran an Anova using the car package. y~A*B+C A has 2 factor levels, B has 3 factor levels, and C has 2 factor levels (data from two data sets was included in the analysis. C is Experiment 1/2) I ...
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Limiting comparisons for post-hoc Dunn's Test

I used the dunn.test() function to run post-hoc comparisons after significant outcomes in an ANCOVA with ...
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78 views

Post-hoc Power analysis to question a non-significant difference?

so we did this study about surgical success-rates in two groups (n=84 respectively). The outcome is binary (success vs. failure). A priori we expected them not to differ and, indeed, there was no ...
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1answer
44 views

ANOVA vs. t-tests (yet again)

I am aware that there are many questions on this site with basically the exact same title. I have read them all and still want to formulate my question as follows: I am trying to understand the ...
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15 views

Correcting for multiple comparisons when exploring an interaction

You conducted a 2-by-2 ANOVA and you find a significant interaction. This interaction does not tell you the nature of the effect, so you explore it further by conducting two separate t-tests for each ...
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Post-hoc analysis of neural network predictions

I have trained a model in PyTorch. My model predicts results of football games. I hypothesize that certain games in my test-set will have higher accuracy. One of the variables would be the start of ...
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1answer
63 views

Post hoc test for robust mixed design ANOVA using R

I have calculated a robust mixed ANOVA because I have no homogeneity of the error variances nor of the covariances (with a 2 level between-subject and a 2 level within-subject variable). Can I ...
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Do you correct for multiple comparisons in one-tailed t-tests?

I'm collection reaction time (RT) data on participants from the same group tested in 4 conditions (A, B, C, D). Since I have a directional hypothesis (RT of A>B>C>D), I'm using three one-...
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Can I use a posthoc test with two significant main effects and no significant interaction?

I've found similar posts have been asked here, but not exactly with the same question. I have a binary outcome variable (dep V M vs F) and two binary predictors, let´s say predictor 1, with levels 1A ...
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NA values when converting into wide format for Wilcox's robust ANOVA

I have a dataset of more than 10.000 values, with 12 different factor levels that are NOT evenly distributed. For my dataset, Levene's test is very significant which means that the assumption of ...

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