Questions tagged [dunn-test]

Dunn's test is a non-parametric pairwise multiple comparisons procedure based on rank sums, often used as a *post hoc* procedure following rejection of a Kruskal–Wallis test. As such, it is a non-parametric analog to multiple pairwise *t* tests following rejection of an ANOVA null hypothesis.

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

Strange results using Dunn's test [closed]

I am receiving a result that seems very counter-intuitive using the Dunn's test. My data is illustrated in the plot below. I have 5 groups (labelled muscle1a, muscle1b, muscle2, muscle3 and muscle4). ...
HanLisb's user avatar
  • 11
0 votes
0 answers
29 views

When to use an adjustment method for Kruskal-Wallis + Dunn's and which method?

I need to do multiple pairwise comparisons among 5 groups (Treatment 1, Treatment 2, Treatment 3, Positive Control, Negative Control) for different tests and times. Each group has $10$ individuals, ...
Antonella's user avatar
1 vote
0 answers
18 views

Bonferroni-Dunn Critical differences

I was reading about visualizing post-hoc tests and I happened to come across a Python package called Orange. Looking into the package, the function used for calculating the CD value seems to be ...
girlinterrupted123's user avatar
1 vote
0 answers
50 views

Having trouble with my analysis. I have no one to ask. I thought I would post here

I performed an experiment where I shocked fish eggs at different times prior to first cellular cleavage, this was to create tetraploid fish larvae. I have a control group and then 9 treatments (60, 65,...
LUUPE's user avatar
  • 11
0 votes
0 answers
44 views

Dunn pairwise test becomes insignificant between two groups if I add datapoints to the third group

I am doing pairwise comparisons between 5 groups. The Dunn test with Bonferroni adjustment only came out significant for two groups (say A and B). However, when I added 5 data points to one of the ...
Arti Thakur's user avatar
0 votes
0 answers
15 views

Which test to use for 13 groups?

I am conducting a preliminary study on a medical sign. Without going into details, I have 13 types of dermatological diseases (variable x) presenting as skin lesions. In each group there are between ...
stats-uni's user avatar
12 votes
4 answers
2k views

The lack of evidence to reject the H0 is OK in the case of my research - how to 'defend' this in the discussion of a scientific paper?

It is probably best if I give an example because I would like to be well-understood, and I do not know how to deal with the following situation: I analysed, using the Kruskal-Wallis test (post hoc ...
crtnnn's user avatar
  • 103
0 votes
0 answers
189 views

Which post hoc test should I choose - Dunn's Test or Mann-Whitney-Wilcoxon? Analysis of 3 groups of physicochemical data

I am working on a scientific paper comparing physicochemical data from the river and two well rows (3 groups of data) - see example picture: In my study, I want to see if there are statistically ...
crtnnn's user avatar
  • 103
0 votes
0 answers
59 views

Dunn test in R: comparison between levels of a single factor in a 2-factor experiment

For a 2-factor experiment, the TukeyHSD function in R (after a significant ANOVA) can calculate P values for the differences between levels of a single factor (basically, comparisons between the ...
MD P's user avatar
  • 53
3 votes
1 answer
51 views

Bonferroni correction gives weird results in R

I have this dataset: Treatment data T1 0 T1 0 T1 0 T10 0 T10 0 T10 0 T11 0.2 T11 0.2 T11 0.2 T12 0 T12 0 T12 0 T2 0.7 T2 0.6 T2 0.6 T3 0.8 T3 0.7 T3 0.8 T4 0.3 T4 0.3 T4 0.4 T5 ...
MD P's user avatar
  • 53
0 votes
0 answers
60 views

Seemingly strange result for Dunn test after Kruskal-Wallis test

I have the following data for three treatments used on a subject. Each subject is observed and given a quality value of 1-5. The numbers in the table represent the number of subjects in each trial ...
Wilhelm's user avatar
  • 153
3 votes
1 answer
52 views

Test on significant difference

I need to test if there is a significant difference in leakage between prototypes. I've tried kruskal wallis and post hoc wilcoxon pairwise and Dunn-Bonferroni test, and the post hoc test always say ...
rklk sek's user avatar
4 votes
1 answer
628 views

Questions about Dunn's test

Authors in a paper state that they use the 'Bonferroni-Dunn test' as a post-hoc test. Is the 'Bonferroni-Dunn test' just a Dunn's test with Bonferroni adjustment or is it a different test (after ...
user378377's user avatar
0 votes
1 answer
446 views

Why do the results of Dunn's test in GraphPad Prism and R differ?

I have three sets of data, to which I want to apply Dunn's test. However, the test shows different results when performed in GraphPad Prism and R. I've been reading a little bit about the test here, ...
Daniel Valencia C.'s user avatar
0 votes
0 answers
394 views

Run Kruskal-Wallis (and Dunn's Test) with multiple responses in R

I want to compare three groups with each other and have chosen the Kruskal-Wallis test and then the Dunn's test as post-hoc test. If I have a data set like this: ...
Multiple_Testing's user avatar
0 votes
0 answers
671 views

Dunn's post-hoc Test after Kruskal, 'which one is more effective?' after significant difference

Dunn's test yielded the result that there is a significant difference in revenue between group 1 and group 2 after Kruskal. In classic one way ANOVA case, if the result is same as above, you see ...
Dan K's user avatar
  • 63
1 vote
0 answers
15 views

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). ...
user2705000's user avatar
1 vote
1 answer
2k views

How do I interpret the p-value in a Dunn-test?

I conducted a Kruskal Wallis test for my sample sizes, and this is what I got: Kruskal-Wallis chi-squared = 12.138, df = 4, p-value = 0.01635 The p-value is below 0.05, so I know there is a ...
bbqhands's user avatar
0 votes
0 answers
3k views

Is the Conover-Iman post-hoc test is better to use than Dunn's with small samples size after the KW test since it use the t-test on the ranks?

I know that we use the t-distribution to be able to know if two small-size samples with a normal distribution (n < 30) are different or not (Student's t-test). If we have a bigger sample with a ...
Simon Leclair's user avatar
4 votes
2 answers
2k 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 ...
Simon Leclair's user avatar
1 vote
1 answer
2k views

Adjusted significance level in SPSS for Kruskal Wallis Post Hoc Test - Bonferroni adjustment

I am making a pairwise comparison using Dunn's post hoc test with Bonferroni correction. However, I am a bit confused on the interpretation of the adjusted significance on SPSS. I am making 10 ...
Louise's user avatar
  • 15
0 votes
1 answer
2k views

How to report? Significant difference for Kruskal-Wallis test, but not for ad hoc pairwise comparison with Bonferroni

I performed Krusal-Wallis test in SPSS and got a borderline significant P (0.042). then, the post hoc pairwise comparison with Bonferroni-Dunn correction showed no pairwise significant difference. I ...
boyuan's user avatar
  • 3
1 vote
1 answer
495 views

Should I rank my data before doing post hoc Dunn test?

I am trying to compare multiple algorithms using the Friedman test and post hoc Dunn test. I know that we should use the rank of our data before performing the Friedman test, but should we rank the ...
Sajjad's user avatar
  • 11
1 vote
1 answer
222 views

Why does my omnibus test do not agree with post hoc test?

So I am running a simple Dunn's Test on my data. After running the Kruskal-Wallis H Test, it returned a result ...
Tyler Ruddenfort's user avatar
1 vote
0 answers
245 views

Bonferroni adjusted p values (from a dunns test)

Are these P values to the same alpha value; ie, if adj p > 0.05 then there is no significant difference? also what does it mean when p = 1 (because this has happened for some of mine yet none of ...
jack23's user avatar
  • 85
2 votes
1 answer
2k views

Dunn test and specific comparisons

What I need is a non-parametric alternative for Dunnett test to compare several groups with a control group (not all pairwise comparisons). And I realise that a specialised test is more appropriate ...
lapotok's user avatar
  • 23
0 votes
1 answer
181 views

Choosing the right test to compare the difference in mean between 3+groups according to the data we have (param vs non-param, sample size..) [closed]

I hope everyone who reads this is fine. I come to you for help, I am a student in data analysis, but I am not yet familiar with everything, especially regarding tests. I have 3 groups of independent ...
user avatar
2 votes
2 answers
884 views

How to get the standardized z-statistic from dunn.test-package in R?

Sorry if this is a trivial question, but I couldn't find anything on it. I am running a Dunn-test with the dunn.test-package: ...
Jory Helmer's user avatar
2 votes
1 answer
2k views

Is Dunn-Sidak approach in MATLAB multcompare identical to so-called Dunn's test?

I've asked the same question elsewhere. These two articles recommend Dunn's test as non-parametric post hoc multiple comparison test following Kruskal-Wallis test. How the Dunn method for ...
Kouichi C. Nakamura's user avatar
0 votes
1 answer
717 views

When doing FDR correction in graphpad prism after Kruskal-Wallis does the programme automatically perform a Dunn test?

I used the Benjamini-Hochberg FDR correction in graphad after performing a Kruskal-Wallis test. This gives me a list of individual P-values. The graphad website says that if you select the FDR ...
GerardP's user avatar
2 votes
1 answer
665 views

Likert Analysis - Dunn's Test (Stata)

Similar to previous questions but I'm still a little confused as to whether I've followed the right process/understood the results correctly. For a research project I'm conducting I used Likert ...
user265151's user avatar
0 votes
0 answers
33 views

Is Kruskall-Wallis H test suitable to influence marketing plan after survey?

I've run a survey which received around 270 responses from a population of around 5,500. The survey asks brief demographic questions followed by opinion questions, akin to the following: Demog Q 1: ...
ukosteopath's user avatar
1 vote
0 answers
24 views

Difference in adjusted pvalues for comparisons between classes when using complete data and only two classes using dunn.test::dunn.test() in R

I am studying carbon content between land cover classes in patagonia and I want to test for statistically significant differences in my data. Since my data doesn't follow a normal distribution, I ...
Benja Sotomayor's user avatar
1 vote
0 answers
19 views

Statistical Comparison of Algorithms by User Ratings

I have an experimental setting where I compare 3 algorithms on the same dataset(n_sources), through user subjective evaluation of the produced outcomes(each algorithm does a different kind of sound ...
MrT77's user avatar
  • 165
0 votes
3 answers
4k views

Dunn's test: is it appropriate to use p-values to interpret relative between group similarity

For a set of data that I collected, I used the Kruskal-Wallace test to determine whether there were between-group differences in the parameter I measured. It returned a significant result, so in order ...
Roxanne's user avatar
  • 13
0 votes
0 answers
141 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 ...
Dunn Wallis's user avatar
1 vote
1 answer
2k 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 ...
Jack Arnestad's user avatar
2 votes
1 answer
14k views

What are the (practical) differences between Tukey's HSD and the Dunn-Sidak correction procedures?

I have a data set with three groups, one of which is a control and the other two groups have been administered either a moderate or a high dose of a drug. The data are not normally or log-normally ...
Sia's user avatar
  • 139
4 votes
1 answer
372 views

Is it appropriate to remove meaningless pairwise comparisons from a post-hoc analysis before correcting for multiple comparisons?

I have four individual groups with two controls and two interventions. The second control group is specifically related to the first the intervention group, making the comparison to the second ...
user195769's user avatar
0 votes
1 answer
1k views

Problem with Dunn's post hoc test to compare a lot of groups?

I have a dataset were people sampled litter at 12 different locations. As the data does not have homogeneous variances I performed a Kruskal Wallis rank sum test (which came up significant) and ...
Stockfisch's user avatar
1 vote
0 answers
1k views

Does Dunn Test require multiple comparisons correction?

If I compared 8 groups with a single Kruskal-Wallis test and it came back positive (<0.05), and then was interested in conducting a Dunn Test to determine which pairs differed between each other, ...
RV1994's user avatar
  • 35
1 vote
0 answers
643 views

Dunn-Bonferroni: All three differ significantly?

I have this huge knot in my head while writing my thesis atm. I am totally untalented when it comes to statistics, so it could be that my question is easy to answer for some of you. I did a Kruskal-...
Stefanie K's user avatar
2 votes
0 answers
2k views

Comparing count data from multiple groups, Kruskal-Wallis with Dunn post-hoc or GLM with Poisson distribution?

Stats novice. I am comparing counts of microplastic artefacts from multiple independent sites, my null hypothesis is that there is no difference in counts between the sites. So far I have tried ...
Gavin Senior's user avatar
2 votes
0 answers
1k views

Mann Whitney U test or Kruskall-Wallis + Dunn test as a post hoc?

I performed a set of inhibition experiments where Lactobacilli supernatants where tested against a pathogen cell culture. These experiments were carried out in a 96-well plate where pathogen was ...
Neuls's user avatar
  • 25
1 vote
0 answers
830 views

How to read the result of of posthoc kruskal dunn test?

How to read the result of of posthoc kruskal dunn test? Specifically, what do the values in the table below tell me? I have 6 treatments and I first did a Kruskal-Wallis test to confirm that the ...
Stat Newbie's user avatar
3 votes
2 answers
2k views

Is it possible to get a CI for the difference in median response between two groups via Dunn test?

Dunn test for two groups is equivalent to Kruskal-Wallis. The null is the absence of stochastic dominance, but if we impose some more restrictions we can assume that the null is the equality of ...
James's user avatar
  • 2,880
0 votes
0 answers
822 views

How do I know which of my groups are significantly different? Kruskal-Wallis, Dunn's test

Answers to other posts that are almost identical to my question are still confusing to me... my data is nonparametric, unequal sample size, unequal variance, so I've decided that kruskal-wallis is ...
bananna's user avatar
  • 73
1 vote
0 answers
203 views

Multiple comparisons and power analysis

I would like to compare 4 different groups for 10 different variables (the biodistribution of a material in different organs). Someone suggested me to use a Kruskal-Wallis test with Dunn's post-hoc ...
David's user avatar
  • 11
1 vote
1 answer
5k views

Interpreting the results of the Dunn test

I've seen some answers that come close to what I'm asking but not quite. I've run a Kruskall-Wallis test that rejected the null hypothesis. Now, I've run the Dunn test, but I'm wondering if I am ...
Ross Wardrup's user avatar
0 votes
1 answer
4k views

How to report the results of a Dunn's multiple comparisons test

I am a bit confused about Dunn's Multiple Comparisons test. My data are non-normal, and I'm comparing the sizes of fish in different years. Here's what I'm not sure about: 1) What is compared? Dunn (...
James Abbott's user avatar