Questions tagged [post-hoc]

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

Filter by
Sorted by
Tagged with
1
vote
0answers
11 views

Post hoc comparisons following nparLD

I would like to compute post hoc tests to follow up on results from the nparLD package. In my sample dataset, I have two conditions, "drugA" and "drugB". There are 6 animals A-F and the weight of ...
0
votes
0answers
12 views

How to conduct Holm's procedure for two-sided Wilcoxon signed rank test when conducting pairwise comparisons for multiple classifiers?

I am trying to compare the accuracies of m classifiers on multiple datasets. Following the suggestion of the JMLR'16 paper "Should We Really Use Post-Hoc Tests Based on Mean-Ranks?", I have decided to ...
0
votes
0answers
15 views

Interpreting results of resemblance-based permutation methods: PERMANOVA and PERMDISP?

I am working with an invertebrate data set (i.e., counts of individuals per invertebrate order, captured by pitfall trap) and am exploring trends in community composition in relation to environmental ...
0
votes
0answers
10 views

Mixed models: No significant interaction - post-hoc analysis?

I have a more or less general question about the logic of post-hoc-tests: I did a mixed linear model on the effect of a treatment on well-being. Subjects were randomly assigned to one of two treatment ...
2
votes
0answers
21 views

Mixed anova post-hoc analysis (when do we need to do t-test across all pairs?)

before I decided to ask my question, I actually find several existing questions that are very similar to mine but remain unanswered: Mixed ANOVA post hoc analysis (and multiple comparisons) Mixed ...
0
votes
1answer
46 views

Significant main effect but no interaction which post hoc test to do?

I have an experiment looking at the effect of rearing condition on development of the number of neural networks (ensembles) in mice. I therefore have two factors (Age 3, 5, 7 dpf) and Rearing ...
1
vote
0answers
8 views

Brown-forsythe test showing statistical differences and posthoc analysis Gameshowell not

I have a data sample whose structure looks like the below: Product | Week Nr. | Amount of Sales (USD) When I perform the Brown–Forsythe test, I've got a p-value ...
1
vote
0answers
22 views

What is the design of this experiment and how do i analyze it

I carried out an experiment in two locations. For the two locations, the experimental set up was 95 genotypes of a plant in 3 replicates. For each replicate, I had 3 blocks in which the genotypes were ...
0
votes
0answers
28 views

Post hoc test after a generalized estimating equation (GEE)

It would be great if someone could provide any clue about performing the post hoc test after a significant gee model. In my own case: We have deployed temperature sensors below the canopies of 3 ...
0
votes
0answers
32 views

MANCOVA post-hoc tests for the independent variable

I am running a MANCOVA to test whether the group means for seven dependent variables are equal across three groups, controlling for two covariates. Being the test significant, I can conclude that the ...
0
votes
1answer
43 views

How do I report results from a Tukey post hoc analysis?

I examined all possible comparisons in the Tukey test (here is the chart - sorry it's a little unclear) https://scontent.fybz2-1.fna.fbcdn.net/v/t1.15752-9/...
3
votes
1answer
54 views

Testing differences in variance between groups

I have a hypothesis that a particular intervention/treatment will cause more variation in participant responses to a particular question. The intervention variable is categorical, with five different ...
0
votes
0answers
51 views

emmeans/multcomp in R vs multcompare in Matlab

I am analyzing a dataset with one within variable (Xw1) and one between variable Xb1. The within variable (...
0
votes
1answer
49 views

Why does the Kruskal Wallis test shows a difference but Wilcoxon doesn't find any between the groups?

Why does the Kruskal Wallis test shows a difference but Wilcoxon doesn´t find any between the groups, even tough the rank medians which are tested as far as I know look very different, and Dunn test ...
2
votes
3answers
162 views

Non-significant Kruskal-Wallis and significant post hoc tests

I have done this analysis where in Figure A-D. the Kruskal-Wallis global p-value is non-significant, but the p-value for pair CS and SCS in Figure A however is significant (at P<0.05). I read ...
0
votes
0answers
24 views

Comparing proportions of 3 groups using chi square and z-test

I was wondering if my plan for analyzing my data was appropriate: I am trying to compare proportions between samples from 3 populations (N= 53, 54, and 56). I ran a chi squared test and found a ...
0
votes
1answer
24 views

Current chi-square test of homogeneity POST HOC analyses in R

I am looking for a currently-working method of running a chi-square post hoc test. I've run a chi-square test of homogeneity using chisq.test from stats, however, ...
2
votes
1answer
93 views

Do I need a Bonferroni correction on a 2x2 chi-squared analysis?

I'm really hoping someone here can help. I have performed a chi-square test of independence, looking at men/women and early/late drop out from therapy. I have a p-value of 0.047. Do I need to do any ...
0
votes
0answers
52 views

Are the posthoc results of the Linear Mixed Effect model valid?

I'm running a linear mixed model on a data frame that consists of 3 variables: ID (n=11), region (n=3) and ...
0
votes
0answers
46 views

Post-hoc test for survival analysis

How can I do a post-hoc test for survival analysis to reveal which groups differ significantly? I have four groups (with 40 individuals of each) treatened by different chemicals. All of the ...
0
votes
0answers
27 views

ANCOVA - adjusted dependent variable and t-test

I have a data set consisting of one independent variable $A$ with two levels/groups (e.g. patient = 1 & control = 0), continuous covariats $X$ and a continuous dependent variable $Y$. Here we ...
1
vote
1answer
45 views

post hoc pairwise comparison

I have a model testing whether the modifications to my texts (fixed factor: Modified) affect several measures (for example IA_FIXATION_COUNT). The Texts used in my experiments are 8, and when i want ...
2
votes
2answers
42 views

linear mixed model - post hoc tests for categorical variables against fixed value null-hypothesis

I'm fitting an LME (with lmer in R) with one categorical variable that has many (80) different values. A fitting example for my problem would be how weight loss ...
0
votes
2answers
52 views

Multivariate post-hoc tests and multiple comparisons

My research group is currently working on a medical imaging project in which we are studying brain perfusion in patients affected and unaffected by a particular type of injury using a technique called ...
1
vote
0answers
30 views

Do I have collinearity?

this is my first post on this forum. I'm a masters student and have a question regarding my experimental setup. I collected arthropods in six vineyards, each vineyard with two plots (a treatment and a ...
0
votes
0answers
25 views

Post hoc for ordinal mixed model with multilevel categorical predictor

I have conducted an ordinal mixed model with four predictors; all of which are either ordinal or multilevel categorical. In my model comparison, I've found significant main effects and interaction, ...
1
vote
0answers
16 views

Why several studies change logical paired/unpaired assumption from omnibus to post-hoc?

There are several studies of highly-referenced researchers where a paired post-hoc test (e.g. Wilcoxon signed-rank) follows the omnibus unpaired test (e.g. Kruskal-Wallis): From Huang et. al "THE ...
0
votes
0answers
43 views

Multiple ANCOVAs: Post hoc Bonferroni, FDR, or can I use MANCOVA?

I am comparing a protein level in multiple (40 to 4000 depending on the analysis) brain areas across three diagnostic groups, with a couple of covariates. I am using ANCOVA to compare the three groups....
0
votes
1answer
79 views

Is it possible to do a Tukey HSD test on a Two Way Repeated Measures ANOVA in SPSS?

I want to undertake a Tukey HSD post hoc test on a Two-way Repeated Measures ANOVA in SPSS 25, but the option to select the test is unavailable. In SPSS I go to: Analyse > General Linear Model > ...
0
votes
0answers
14 views

Can I use UNPAIRED post-hoc analysis for PAIRED omnibus testing?

If I have a omnibus statistical test with unpaired assumption (e.g.Kruskall-Wallis), could I ever use the opposite (paired) post-hoc analysis? (e.g. Wilcoxon signed-rank for post-hoc analysis of ...
0
votes
1answer
48 views

Is it possible to get non-significant post hoc test in a significant ANOVA test while the unpair t-tests are significant? [duplicate]

I conducted One-Way ANOVA to compare means in 4 groups. The ANOVA was significant, but the post hoc tests were non-significant. Then, I applied unpair t-tests to compare each group to the lowest group....
0
votes
0answers
47 views

Post-Hoc Test for RxC Contingency Table

This question extends Meg's question and Glen_b's comments/answer found here. I'm wondering about the appropriateness of two approaches to conducting post-hoc comparisons following the (omnibus) chi-...
0
votes
0answers
27 views

Compare changes between groups over time

I have 2 groups (genotypes WT and KO) of indivuals for whom I obtain their weight each month during a year. The simple question I want to answer is: Do the WT group gain more (or less) weight that KO ...
0
votes
0answers
65 views

Games-Howell Post-Hoc Test Results Not Expected

I ran a Welch's test in R to see if there were differences between my total deer density (deer per square mile) and the size of my reduction area (1, 5, 10, 15, 20, and 25 square miles). The summary ...
0
votes
1answer
59 views

Reporting results of a GLMM with Helmert contrast in fixed effects

I would like help deciding how to report my results. I am looking at whether different demonstrations affect performance in a forced-choice binary task. Demonstrations were done either by a puppet or ...
0
votes
0answers
27 views

Post Hoc Tests with a lm model where model assumptions are violated

I have the following data set: dependent variable is carbon levels in manure. Independent varibale is the month that the manure was collected in (12 level factor). I want to test if there is a ...
0
votes
0answers
27 views

games-howell test with multiple independent variables

my data doesn't meet the homogeneity of variances criterium. After a welch one way test I wanted to perform a post hoc games-howell test since it doesn't require the homogeneity of variances criterium....
0
votes
0answers
33 views

Kruskal–Wallis vs Mann–Whitney when comparing pairs

I am wondering the following. Given a dataset of measurements of one sample under 7 different conditions, which test is the most accurate and appropriate to use when comparing each two of the ...
0
votes
0answers
59 views

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 ...
0
votes
0answers
20 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 ...
2
votes
2answers
456 views

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 ...
1
vote
1answer
85 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 ...
0
votes
0answers
14 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 ...
0
votes
0answers
593 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 ...
0
votes
0answers
31 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 (?) ...
0
votes
0answers
34 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. ...
0
votes
0answers
43 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?
2
votes
0answers
54 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 ...
0
votes
1answer
47 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 ...
0
votes
1answer
47 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 ...