Questions tagged [kruskal-wallis]

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.

286 questions
Filter by
Sorted by
Tagged with
25 views

Advise for two non gaussian distribution group

I have a dataset which test the introduction of a new measure of a luggage checking a local small airport, the aim is to conclude whether the new measure reduce the luggage checking time. My dataset ...
14 views

How to interpret the kruskal wallis test in r

I am trying to understand the results on the kruskal wallis test that are produced in R. The data that I am testing: ...
9 views

In scipy why stats.kruskal can work with two populations?

Krustall-wallis testing should be working only at least with 3 populations.But here, it seems to accept 2. Krustall-wallis extends the Mann–Whitney U test, which is used for comparing only two groups....
11 views

Is Serial Independence, an assumption in Friedman and Kruskal Wallis Tests

I understand that Friedman and Kruskal Wallis are non-parametric tests to see if different groups come from same population. I also gather from here that these tests are used to test for seasonality....
41 views

Can Kruskal-Wallis test be used in groups of different size?

I am trying to compare Likert-scale answers to a survey applied in 3 different cities: A, B and C. I arbitrarily chose twice as many respondents from A, for a total of 500 answered questionnaires in ...
46 views

What to do when assumptions of both ANOVA and Kruskal-Wallis are violated?

I am trying to analyse whether three groups (samples sizes 27, 26 and 23) differ in their responses to 20 questionnaire items, each measured using a 5-point likert scale. The items are all ...
73 views

Can I use multiple regression on a ranked response variable as a significance test for multiple covariates?

This blog post illustrates the relationship between inference tests on groups (t-test, ANOVA, etc.) and equivalent linear models. It also claims that for reasonable sample size, regression of a ranked ...
36 views

What is exactly the non-normality requisite for nonparametric tests? [duplicate]

As the title says, what is exactly what is being tested before deciding to use a non-parametric alternative test (as Kruskal-Wallis for ANOVA, or Mann-Whitney's U for student's t)? Most sources are ...
15 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 ...
13 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 ...
40 views

Statistical Analysis of 3 groups(parameterisation of same algorithm) under the same dataset: non-repeated measures or repeated-measures?

I'm analyzing the performance of 3 parameterizations of the same algorithm under the same dataset. This performance is user-evaluated under a single Likert-type item (5-values). Given the ordinal ...
30 views

is Kruskal- Wallis test appropriate in this case?

Does this make sense, is this test appropriate in order to see how responses differ among more then 2 different groups? I have no experience working with SPSS. Is there any chance someone can help me ...
64 views

Kruskal-Wallis and Negative binomial regression do not agree

I am comparing the number of broods made by dung beetles (Brood_Number) across three temperature treatments (Temp_Offset, a 3 ...
42 views

Multivariate test for likert scale data in r programming

I have a data of likert scale type, collected to know the 'level of awareness of individuals' about various investment options. I want to check if there is significant difference in level of ...
73 views

Effect size calculation for Kruskal-Wallis mean rank test

I have a published paper in which I'm attempting to calculate the effect sizes for various outcomes. For a pre-post scale, the authors report the sample size, mean rank, and p-value for an outcome (...
48 views

Comparing heteroscedastic groups with sample sizes from 1 to 24… No valid tests?

I'm comparing 1 continuous variable across 36 groups (nurses grouped into 36 hospital units). Several groups have only 1 observation, but most have more, ranging from 1-24 observations per group. ...
25 views

Small sample size ANOVA

I am working with monthly results of some variables, and I would linke to compare weather 6 years are statistically different or not, so my saple size per group (year) is bounded by 12. I ran Shapiro ...
24 views

Independent or matched groups?

A very beginner level question here: I'm trying to see whether there is a difference in how students assess the usefulness of 5 possible courses to be added to their curriculum. Each student was asked ...
30 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 ...
31 views

Is the ICC appropriate here?

I have N tissue samples, labelled as either A or B. 2 measurements are taken from each sample. The data is not normally distributed. I'm interested in 2 things: firstly, whether there is ...
38 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 ...
37 views

What is the appropriate test when dependent variable is ordinal binary and independent variable is continuous?

I am curious what is the most appropriate test to use when the outcome variable is an ordinal binary (test score of pass or fail) with a set of four unordered treatment conditions (A,B,C,D) as the ...
30 views

Weighted Kruskal-Wallis Test and Questions

I am currently studying the prevalence of a particular disease among eight different subgroups (for example, the prevalence of hepatitis B among HIV+ patients, HIV- patients, etc.). Each subgroup ...
132 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 ...
9 views

Appropriate analysis for univariate proportion data and environmental variables

I'm new to statistics so am trying to choose the best analysis to find if; There is a difference between canopy cover (0-100%) at different sites There is a relationship between canopy cover and ...
18 views

Friedman and Kruskal

I have a data with 4 groups and multiple variables with measured values. my groups are ES, EP, PP and PS. ES and EP are associated and PP and PS are too. So i would like to compare my groups in non ...
57 views

What test do I use for this? (NOOB biostatistics question)

Suppose I have some subjects and I give each of them a test. I would end up with a dataset like: ...
42 views

Mann-Whitney (2 groups) contradicted by Kruskal-Wallis (3 groups)

We have two groups that are significantly different (tested with Mann-Whitney). When a third group is added, the Kruskal-Wallis tests provides a non-significant result. This implies that two or more ...
54 views

Is this a valid approach to hypothesis testing

I have been a machine learning hobbyist for a while now and am attempting to formalise my understanding of the statistical foundations to data analysis and machine learning. My reading so far has ...
40 views

Comparing means in large samples: effect size and p-value

I have a large sample (10000+ per location) of temperature measurements which I would like to compare between 3 locations. I'm checking if there is a significant difference in temperture means between ...
46 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 ...
136 views

Is it correct that JMP has Mann-Whitney U for comparing more than 2 unpaired groups (instead of Kruskal-Wallis)?

To the best of my knowledge, the Mann-Whitney U test (also called Wilcoxon-Mann-Whitney) is for comparing only two unpaired groups, while the Kruskal-Wallis test is used for comparing two or more ...
70 views

What is the point of a permutation F-test when all you need is one F-test for one-way ANOVA?

Say you have three groups, and each group has 5 observations. You can figure out if there is a significant difference between means with a simple one-way ANOVA. I read in my nonparametric book, one ...
95 views

Normality vs normality of residuals

I am currently trying to perform a hypothesis test on the difference between four means. Initially I was trying to use ANOVA but then realised I may not meet the assumptions for this test and may need ...
75 views

Reporting insignificant results using mean ranks

I have a number of non-significant results from a Kruskal-Wallis test and wondering the best way to report them. My independent variable is 3 categories: Group A: Uses product A; Group B: Uses ...
29 views

Statistical test to use to test mean equality given non-independence assumptions

In a survey conducted, 75 survey participants were asked to rate randomized keywords from groups 1-5. Every keyword belongs to a group and subjects were asked to rate each keyword. I would like to ...
59 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 ...
18 views

How to test for differences between groups for ordinal outcome variables in SPSS?

I do not have experience with ordinal data, please help me out with my questions? I have conducted a survey which consists of 25 Likert-items, these items are all statements for certain conditions ...
146 views

How can I calculate confidence intervals for epsilon-squared (Effect size for Kruskal-Wallis test) in R? [closed]

I'd like to calculate the confidence intervals for the epsilon-squared effect size statistic in R. Here is the code I'm using to calculate the epsilon-squared value: ...
148 views

Should ANOVA be used when the dependent variable is an integer, such as a count of items? [duplicate]

I have data for a dependent variable, DV, representing a count of objects, with a range from 0 to 6 (sample size 450), slightly left skewed with a mode at 4: Furthermore, I have a single categorical ...
33 views

Comparing 3 groups at 2 time periods

I'm analysing a dataset and comparing three zones at two points in time. The data in question is: Hourly sightings of wild fish (CPUE) In one of three adjacent zones (A, B, and C) During the ...
341 views

Mann-Whitney U test or Kruskal Wallis test for comparing median of two groups?

I know that Kruskal Wallis test can be used to compare median of two or more groups (e.g. see this link: https://www.statisticshowto.datasciencecentral.com/kruskal-wallis/ ), and that Mann-Whitney U ...
18 views

Using Multiple Comparisons for Kruskal Wallis Follow up analysis

I am performing the Kruskal Wallis test on ~100 samples and wish to group statistically ‘similar’ samples together. The method I am using is described in Andy Field’s ...
24 views

Pair-wise ANOVA or non-parametric comparison

I'm doing an experiment with 7 groups (batches) of 12 measurements of a certain chemical, where one group (b0) is considered the baseline case. The research question is to find out which groups have ...
2k views

Meaning of chi-squared in R Kruskal-Wallis test

I have a simple question to ask, I think it was not covered in other questions. I am running a Kruskal-Wallis test in R, using the function kruskal.test. The output gives me the p-value and a chi-...
63 views

Non-parametric test for interaction effect

I have a relatively small data set with quality ratings (dependent var), for different compression methods (independent var 1) applied to different types of video (independent var 2). My first ...
193 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 ...
25 views

Is my analysis approach and decision valid?

I'm busy with a class assignment and I would appreciate a second pair of eyes on my analysis approach. A part of me feels that I'm overthinking this or have done an unnecessary test. Context: Use 4 ...