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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1answer
86 views

What does comparing mean rank mean?

Lets assume that I am having 2 samples: Sample A 20 20 20 20 25 and Sample B 1 2 3 4 5 If I want to compare these two samples ...
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1answer
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Kruskal-Wallis possible?

Let's assume the group variable is the dependent variable and can have the values [A,B,C,D]. It is nominal. The independent variable is ordinal and can have numbers between 0 and 5. I want to test for ...
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21 views

Specifying non-linear mixed effects models or non-parametric ANCOVA in R (non-linear DV and covariate)

I tried running a standard mixed model in lme, and the residuals were highly non-normal, now I want to do a non-parametric version with a covariate and am having trouble. More details and data below. ...
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33 views

Variance analysis for overlapping samples (resulting from multiple choice questions)

How do I check if multiple groups are different regarding a certain property, if these groups overlap? Example I conduct a survey and ask participants two questions: ...
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1answer
38 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 ...
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14 views

Should I apply Kruskal Wallis test?

I am doing research about the purchasing behaviour of the population. Therefore, on my online survey, I have questions about the effect of the advertisement on social media on behaviour. So, the ...
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21 views

Effect of non-independence of data on ANOVA and Kruskal-Wallis H-test

I have some data consisting of the number of people visiting a shop each day for the past few years. I would like to investigate whether there is a "day-of-week effect"; that is to say, I ...
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54 views

Can the Kruskal–Wallis test be used to compare two time series?

I'm trying to compare two time series and determine whether they have similar distribution, trends, seasonality etc. So far, I've seen that Dynamic Time Warping and auto-correlation plots can be used ...
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31 views

Statistical analysis on values that are not exact but above or below a limit (e.g. >100, or <5)

I have a data set with a small number of bioreplicates (3-10) per sample, and I am assessing whether each sample is statistically different from the wildtype control using a Kruskal-Wallis test with ...
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1answer
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Choice of statistical tests - Kruskal-Wallis for categorical, continuous, and ordinal outcome data?

I have 2 groups of medical students (50 in each group) that have each used 3 different techniques to undertake a procedure on 12 patients. So, 3,600 data points but accepting that they are not truly ...
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Which form of stochastic dominance is tested for using the Kruskal-Wallis hypothesis test?

The Kruskal-Wallis one-way analysis of variance has the following interpretation reported on wikipedia: A significant Kruskal–Wallis test indicates that at least one sample stochastically dominates ...
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How to perform non-parametric test (e.g. Kruskal Wallis) on nested data in R

I have a dataset of non-parametric data that contains plant height at 16 sites, 4 of which are under treatment A, 4 under treatment B, 4 under C and 4 under D. Originally I performed a Krukal-Wallis ...
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1answer
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Using Kruskal–Wallis test on large data sets

My research involves a huge number of data points (millions). I have one independent variable with 3 groups (patent organizational type (University/Industry/Collaborative Patent)) and 4 ordinal ...
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kruskal-wallis and boxplots interpretation

This is an example. Let's say in my investigation I am collecting online text data. I have a software that automatically collects text according to specific categories. I have to select the best ...
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1answer
54 views

What are `rms::orm`, `wilcox.test`, and `kruskal.test` (in R) doing differently?

Much like the two-sample (equal variance, not Welch) t-test is a special case of ANOVA, and ANOVA is a special case of linear regression, the Wilcoxon Mann-Whitney U test is a special case of Kruskal-...
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1answer
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ANOVA or Chi-squared Test, which test should I use?

I have an depentent variable which means agreement, it is a value between 1 and 6 (integer) 6 means more agreement than 1. I have two categorical variables: Level of experience. Value from 1 to 4. 1 ...
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ANOVA is to ANCOVA as Kruskal–Wallis is to...?

ANCOVA is an ANOVA with an added covariate, and I find it quite elegant how both can be seen in a general regression framework. If, however, I want to do a Kruskal–Wallis-type of test that accounts ...
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What non-parametric statistical test can I use that compares difference taking into account 2 independent variables and 1 dependent variable?

What non-parametric statistical test can I use that compares the significance difference taking into account 2 independent variables and 1 dependent variable? For example, The first independent ...
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1answer
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Step-by-step explanation of Likert scale/item statistical analysis?

I am looking for resources (books, online, articles) which have a step-by-step explanation of how to test hypothesis using Likert scale/item data. So far, I've learnt that non-parametric methods are ...
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1answer
35 views

How to use Kruskal-Wallis to check if continuous variable Y has correlation with categorical variable X?

I used Kruskal-Wallis on my data that has a continuous Y variable and categorical X variable (more than 2). I got the following result: Statistics=784.547, p=0.0000 with alpha: 0.05. What does this ...
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37 views

Kruskal-Wallis test for ranking data

I have a complex experimental design where there are 3 groups, and in each group, a ranking/comparison is made between items (list of items). Each ranking is associated with 9 measurements on a 5 ...
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How to interprete when data is statistically significant with longitudinal mixed effects but not Kruskal Wallis/Welch Anova?

I have a repeated measures experiment with each case being measured at 3-4 timepoints. The cases are grouped into three groups. When I analyze the measures within each timepoint e.g. timepoint 1, ...
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Comparing differences between three or more unpaired groups (DV categorical and non-normal continuous) and describing used tests

I have a made-up table as follows, including a footnote describing given p-values. P-value shows the differences between all subgroups, and it was derived from the Kruskal-Wallis test for continuous ...
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17 views

Should I use a parametric test or non-parametric test?

I'm analysing a set of data on the fluorescence intensity of a particular receptor. All the data are in the form of a fraction as they are being compared to a control. ie. fraction = intensity of test ...
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What is a good location equivalence test for comparison of small and large samples?

I have two one-dimensional samples, one is small (like 2 values) and another of a larger size (several dozens). I want to estimate the probability that the two samples are drawn from different ...
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2answers
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Kruskal-Wallis post-hoc analysis [duplicate]

I am doing a Kruskal-wallis test and am wondering which post-hoc analysis is the most suitable for this? Been reading around and saw people recommend Dunn test. I am just wondering if there is any ...
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Need to test heteroscedasticity before using the Kruskal-Wallis test

My question is whether or not I have to test heterodasticity before using the Kruskal-Wallis test. What I understand is that if I want to compare medians, then I have to check for heteroscedasticity, ...
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32 views

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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20 views

Test for Nominal Response Vs Continuous Predictors? (R)

I cannot find much information on this, none so-far useful. I have a sparse data set with 17K+ columns of continuous gene expressions, an example of a typical column: (3.15, 0, 7.1294, 0, 0, 0, 2300.2,...
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What kind of ANOVA is appropriate for a single grouping with correlated measurements?

Lets say I have a bunch of meteorologists who all attempt, at the start of each day, to estimate the max temperature that will be observed for the day, for a whole bunch of weather stations dispersed ...
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1answer
76 views

Can I use Kruskal Wallis test to analyze ranked data? If not, what analysis method should I use?

I am currently conducting a survey study for a project. Unfortunately, I would not at all consider myself proficient in statistics, and am struggling with choosing the appropriate analysis method for ...
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60 views

Is there a way to calculate the magnitude of the difference in means in R?

I have a dataset with a non-Gaussian distribution - signalment and body measurements of three species of bird. I have used the Kruskal-Wallis with post-hoc Dunn Test and Bonferroni correction tests to ...
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16 views

Statistical test appropriate for comparing frequencies between groups

I have a table with frequencies of a gene inheritance between two groups as shown below: Genus Paternal Maternal Bi A 260 40 50 B 5 30 25 I want to test whether (i) frequencies among the ...
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0answers
5 views

Are the data grouped by different drug doses graded data or disordered data?

I have a set of data, the structure is as follows: 5mg 10mg 15mg 20mg Survive 15 22 18 24 death 3 2 3 2 I divided the patients into 4 ...
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30 views

Visualising significance of difference between nominal groups

I have a data set that gives the number of issues found during annual vehicle inspection for various car models and it probably is a vague requirement but I need to come up with a way to visualise ...
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134 views

Multi-Factor Kruskal Wallis Test in R

I have a dataset where the response variable is a non-normally distributed proportion and is heterogenous with respect to all factors. I cannot seem to transform the response variable into anything ...
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24 views

Comparison of medians in data with multimodal distributions

I'm comparing continuous data obtained at two different time periods with the distributions seen below. They appear fairly similar, but they're clearly non-normal. The ideal hypothesis is that the ...
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1answer
22 views

Testing for difference in distributions of Likert-scale data that differs only in a median-preserving spread

Assume that I have a Likert scale with five categories, coded as {1, 2, 3, 4, 5} and that I have two samples, the first of which is generated by drawing from a uniform distribution over these five ...
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133 views

Kruskal-Wallis Test effect size: Can it be greater than 1?

The Kruskal-Wallis Test effect size can be calculated based on the formulae from the article, once the Kruskal-Wallis H-test has been computed, the epsilon-squared estimate of effect size can be ...
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19 views

Kruskal Wallis test for two samples returns error in a particular month

I am performing the Kruskal Wallis test in R to check the similarity/differences between samples in 6 pairs; each pair has two samples. Just to be clear, the pairs are not being compared to each other....
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6 views

Testing equality of variances in very small samples

If I have two very small samples with i.e. 3 or 4 observations and I would like to check if their variances are significantly different from each other. However, when I want to apply the Kruskal- ...
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12 views

Calculate power of the Kruskal-walis test [duplicate]

I think this has been asked before on here but it didn't get a straight answer. I would prefer to do it in R if possible.
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1answer
327 views

Can Kruskal-Wallis be used for discrete data?

I have a data frame with variables that are counts, nominal (two groups) and continuous. Two of the continuous variable follow a normal distribution; the counts variables do not follow a normal ...
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0answers
13 views

Comparison of property of 5 treatments with just 4 observations each

I have a small dataset with 4 observations per treatment. My plan was to do an ANOVA, so I checked the response variable for normal distribution with Shapiro-Wilk for each treatment and there was one ...
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0answers
8 views

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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0answers
21 views

What statistical test to perform to find differences between groups that has sub-groups?

I have this dataset (N = 15k) in which there are 17 main variables and 8 topics. The variables are all continuous while all topics are binary. Data ...
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1answer
101 views

Kruskal-Wallis and Mann-Whitney U give different results

For my thesis, I am comparing the importance of "comfort" (measured using a 6-point Likert scale) among four groups of people (participants who prefer traveling by plane, by train, by coach ...
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25 views

Can we do a Spearman's corelation between a continuous and an categorical ordered variable (0,1,2,4)?

just a question that may be already answered here, is it possible to perform a Spearman's rank correlation ( to find a correlation) between a continuous variable and a categorical ( ordered) variable ...
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30 views

Finding meaningful boundaries between two continuous variables in R

To find the relationship between two columns of the iris dataset, I am performing kruskal.test and p.value shows a meaningful relationship between these two columns. ...
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139 views

What does offsets mean in reference to expectations in R package MultNonParam?

I am trying to calculate sample size for Kruskal-Wallis test using kwsamplesize included with the MultNonParam R pacakge https://cran.r-project.org/web/packages/MultNonParam/MultNonParam.pdf. The ...

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