# Questions tagged [kruskal-wallis-test]

The Kruskal–Wallis procedure is a nonparametric equivalent of one way analysis of variance, used for comparing the location of three or more groups; it extends the two sample Mann–Whitney–Wilcoxon procedure.

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### Kruskal with multiple independent and dependent variables

I have three independent variables: latency - ordinal with 4 levels difficulty - ordinal with 2 levels expertise - ordinal with 2 levels And three dependent variables: time - cardinal scale (just ...
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### Mann-Whitney-U and Kruskal-Wallis give different results, two categorical data

I've read the KW test is typically used for nonparametric data with 3+ categories and large sample sizes, but it can be used for 2 category data as well. As in, the formula will still work and produce ...
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### Should I Apply FWER Correction After Performing the Dwass-Steel-Crichtlow-Fligner Post-Hoc Test?

I have a scenario where I need to compare multiple groups ($N > 2$) with non-Gaussian distributions. After performing the Kruskal-Wallis test and finding a significant p-value ($p < \alpha$), I ...
32 views

### Appropriate way to correct for multiple comparisons in this case

I am trying to compare the performance of an optimisation algorithm on different objective functions. The functions can vary in their form (4 different types) and dimension. I would like to first ...
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### How to compare three groups of patients if one group is normally distributed but the other two are not?

Retrospective study involving three groups of patients. Group 1 are patient's diagnosed with sepsis. Group 2 are patient's diagnosed with a localized infection. Group 3 are "healthy" ...
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### Underlying model ANOVA and Kruskal-Wallis

Is the underlying model for one way ANOVA ($Y_{ij}= u + t_i + E_{ij}$) the exact same for Kruskal-Wallis test since KW is the non-parametric anova equivalent or does it have a different model?
1 vote
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### What Statistical test to use on my project?

I am very confused about what kind of statistical test to use in RStudio on my project, I have measured the mean salinity for 3 levels of population density (low medium and high) across 6 months (...
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### Kruskal-Wallis with unbalanced classes and assumption of normality

Edited I want to better understand: how to appropriately approach a significant test with largely unbalanced classes appreciate the "story" that a statistical tests support Situation: I ...
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### ANOVA vs Kruskal Wallis - Small sample size

I have data from an experiment comparing plant weights for 4 independent treatment groups. The data seem to be normally distributed (I have been warned about using statistical tests for normality). ...
1 vote
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### Welch ANOVA for Comparisons of Elevation & altered Sediment Accretion of Sea Ecosystems: Large DEM with no normal distribution & heterogeneity

I am investigating the elevation characteristics and sediment accretion effects of two distinct ecosystems within the Wadden Sea, impacted by the bioinvasion of one species (ecosystem one) and ...
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### Is Kruskal-Wallis really a good test of stochastic superiority?

After much reading/googling, I reached the conclusion that the Kruskal-Wallis test (K-W) is a test of stochastic superiority (or, equivalently, of stochastic equivalence). Rejecting the null implies ...
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### Statistical approach to explain variance in different types of soil health data (organic material decomp vs lab based measures)

Seeking feedback and guidance on the statistical approach to explain variance in soil health data for a scientific paper on the sensitivity of organic material (teabag) decomposition to commonly used ...
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1 vote
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### I would like to perform a Kruskal-Wallis test in Jamovi [closed]

My problem is that I have data of sexual assertiveness (7 point Likert-scale, SAQ) and relationship satisfaction (5 point Likert-scale, RAS) but I would like to divide the sexual assertiveness ...
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### Statistical test for small non-parametric dataset with more than 2 dependent groups

I’m trying to figure out the most appropriate test to use for a small water quality dataset (n = 10 sampling visits at 6 river sites, upstream to downstream) with the following characteristics: -not ...
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### 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, ...
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### p value <0.05 Bonferroni adjusted but associated descriptive statistics not supportive of difference

I conducted a Kruskal Wallis test on 4 groups of participants' responses on a Likert scale. The likert scale consisted of 5 possible responses. This is from results from a research project I have ...
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1 vote
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### I'm struggling to find which is the right statistical test to use?

I have two variables: cell death and diet, but on the diet variable I have several groups that I want to compare. I was thinking of doing multiple Mann-Whitney tests, but that would be very time ...
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1 vote
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### Kruskal wallis and posthoc test verification?

I am trying to run a kruskal-wallis test on my dataset. Dataset is given below: ...
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1 vote
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### Is there a way to do planned contrasts after a Kruskal-Wallis test in R?

I want to compare three groups: Children, Caregovers and Experts. I cannot do an ANOVA as my data does not meet the assumptions. Therefore, I need to do a Kruskal-Wallis test. For Post-hoc I am ...
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1 vote
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### Adjusting for multiple comparisons after Kruskal-Wallis

I am comparing biomarker levels (50 total) obtained from immunoassay in a cohort divided into 3 groups (control vs. inactive vs. active). I want to use the Kruskal-Wallis test with Dunn’s test to ...
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### Is it appropriate to conduct a Kruskal-Wallis test with the mean of a 3 item construct measured on a 7-point Likert scale as independent variable?

I am working on my master's thesis and conducted two studies. The first study utilizes 3 groups. The problem is, that the group sizes are very small (n1 = 13, n2 = 14, n3 = 14). I want to test if ...
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### Kruskal-Wallis statistical power

Given that the Kruskal-Wallis $H$-test has been computed, the epsilon-squared estimate of effect size can be calculated as $$E_R^2=\frac{H}{(n^2 - 1)/(n+1)},$$ the number of the compared groups, the ...
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### GLM vs Kruskal-Wallis/ANOVA?

I am trying to analyse some data in R that has one continuous dependent variable (x) and two categorical variables (sex: M/F, surface: D/V). My main goal is to understand if sex and surface affect 'x'....
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### Data is not normal, want to test for interaction too Any non-parametric test? [duplicate]

I have a sample size of $310$ individuals that comprises samples collected along the elevation gradient and at different times. I want to see how the variables differ along the elevation, and with ...
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### Non-significant results when running Kruskal-Wallis, significant results when running Dwass-Steel-Critchlow-Flinger pairwise comparisons

I am writing my Master's thesis on adult's performance on cognitive and linguistic measures. I have four age groups and am investigating if there is an age difference in the performance on summarized ...
1 vote
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### 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,...
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1 vote
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### Is it possible to apply a Kruskal-Wallis to data without clear dependent/independent variables? [closed]

I'm trying to find a NHST for my data that, as far as I know, are only compatible with a Kruskal-Wallis test. However, my variables aren't really identifiable as either dependent or independent; ...
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### Kruskal-Wallis Test shows significance, but Pairwise Wilcoxon Rank Sum Test does not

I used the following code to perform a Kruskal-Wallis test on a dataset, which gave me a significant p-value (5.159e-06). However, when I then use pairwise.wilcox.test() to perform a Pairwise Wilcoxon ...
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### Kruskal-Wallis multiple testing - correction alpha

I have 10 numeric outcomes in one dataset and I want to use Kruskal-Wallis test to identify an influence via a predictor variable (group variable) and also for each age group. I am testing for each ...
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### Correctly interpreting a two-sample Kolmogorov-Smirnov test and a Kruskal-Wallis test

I want to confirm my understanding of the two tests referenced in the title. Say I have data on a variable $Y$ from two groups (0 and 1), and I perform the following tests in Stata: ...
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### Do I need to use a factor for the ANOVA? [closed]

The problem: A psychologist is interested in short-term working memory under (1) sleep deprivation, (2) a strong dose of caffeine, (3) following 8 hours sleep. They conduct a between subjects design. ...
1 vote
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### Correct statistical test to model user preferences among multiple models

My problem involves comparing the performance of machine learning models to how good each model's recommendation is. The way I'll design the experiment is as follows: I'll send out a form to multiple ...
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### 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 ...
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### Investigating Group Membership's Impact on Questionnaire Scores: Need Assistance with Kruskal-Wallis Test and Data Analysis

I'm currently working on a research project where I want to explore whether there is a relationship between group membership and scores obtained on a questionnaire. I have three distinct groups, and ...
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### Most appropriate model for 0-10 scale integer data

I want to estimate the effect of a grouping variable (5 groups) on an outcome variable that is an integer and a scale from 0-10. So, for the outcome only scores of 0,1,2,... etc. are possible. This ...
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### Can Kruskal-Wallis test be used for count data?

I collected positive count data, specifically the number of infected leaves per plant, as part of my experiment. To treat the plants, I placed them in the field for a week using four different ...
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### How to Interpret Post Hoc Test Results of Kruskal-Wallis Test?

I have performed a Kruskal-Wallis test to assess the difference in disease severity (recorded on a scale of 0-10) among different months. Here's the code I used: ...
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### Kruskal-Wallis as a non-parametric alternative to 2-way ANOVA?

I'm a master student currently working with taxonomy and cultivation of wild edible mushrooms. In my experiment, I'm evaluating the effect of 4 distinct solid culture media and 4 temperatures on the ...
1 vote
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### What to report with the Kruskal Wallis?

I am analyzing a dataset, where I have 3 categories (independent variable), and one continuous value (dependent variable). I am studying if the continuous value is significantly different between the ...
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### Comparing non-normal data between three groups

I am analyzing a dataset, where I have 3 categories (independent variable), and one continuous value (dependent variable). I am studying if the continuous value is significantly different between the ...
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### Chi2 or Kruskal Wallis?

I have 3 different groups based on their level of resilience : low (n=60), moderate (n=35), high (n=10). After a qualitative thematic analysis of their responses, different subjects emerged, like &...
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1 vote
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### Is this a Kruskal-Wallis Test?

This table shows the results of a Kruskal-Wallis test, but I am not sure what the column values represent. I thought the Kruskal-Wallis test statistic is always positive and that the test merely shows ...
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1 vote
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### Wilcoxon test for two groups or post hoc analysis of K-W test when I woud like to compare two groups and observe the difference?

I am working on data analysis. I divided my samples into five different groups (group A-E) by using some variables. and then, because group A can be further reclassified into group A+ and group A- and ...
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1 vote
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### Best analysis for checking the relationship between two variables when one of them have repeated values

I have a dataset with different measures of plants (height, size of leafs, etc.) in 5 localities. I want to check if there is a relationship between those variables with temperature and precipitation. ...
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### Kruskal-Wallis returns only one significant group (out of 4 groups), when significant group is removed and test redone, another group is significant?

I am comparing 4 groups of samples using SPSS. The groups are 4 bathymetry groups (>0m, >-1m, >-2m, >-3m). Within each group are a number of samples n. Each sample has a recorded seagrass ...
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### Trying to figure out how to test these data - correlation between groups for stratified/range of data?

Apologies if some of my terminology is incorrect, I only have relatively basic stats knowledge. I have two groups of patients where we've done some experiments on the electrical conduction within the ...
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### 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 ...
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### Kruskal-Wallis Test - medians are same but result is significant?

I have run a Kruskal Wallis test in my dataset and have a significant overall result (p<<0.001). However, since the medians for my categories are the same, I can't work out the direction of the ...
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