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Questions tagged [friedman-test]

A non-parametric test for the equality of >2 dependent groups.

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testing whether categorical distributions differ

i have data on how a large population (N ~ 1e8) is distributed into (many) categories (i.e. i have count of instances in each category). some categories have low ...
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21 views

Friedman Test not significant but Post Hoc Tests are?

I am running a Friedman test to find out if there are differences in a ranking between 4 treatments (Drive, Interaction, Track, User). 1 best application, 4 worst application. For example Proband 1 ...
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17 views

NASA TLX Analysis

I am trying to analyze a NASA TLX. The NASA TLX is the de facto standard for subjective workload task load. In my experiment (n=27), participants drove a track in a driving simulator while ...
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30 views

Friedman test with several repetitions

I'd like to run a non parametric test such as the Friedman test on the data of my experiment. I have several algorithms ($n$) which I'm comparing against each other. These algorithms are run on $k$ ...
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32 views

non-parametric test: proof of Friedman's statistic

I am asked to prove that the Friedman statistic has two equivalent forms, namely: This is my attempt at a solution starting from LHS and trying to arrive at RHS. I feel like there are some ...
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1answer
56 views

How to obtain the results of the Nemenyi post-hoc test in a table showing grouped pairs?

I performed a Friedman's test, which showed that there are differences among my treatments. Thus, I choose to perform the Nemenyi's post-hoc test in order to infer which treatments statistically ...
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1answer
39 views

Tukey-Kramer or Nemenyi following Friedman

I previously asked a question here after discovering an option by MATLAB to run Tukey-Kramer for multiple comparison multcompare following Friedman test and many ...
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1answer
66 views

Correction needed for an non-parametric Anova?

I'm trying to analyze the behavioral data of my research experiment and I'm a bit lost... o_O Briefly, subjects undergo 4 different conditions (of increasing complexity 1<2<3<4). At the end ...
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1answer
335 views

How to interpret the result of Friedman's test?

I uploaded the data and then I used bootstrapping to have 10 different samples from the original data but with the same length as the original data. For each sample, I used 7 distance metrics, and I ...
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59 views

RM one-way ANOVA or Friedman test

I here my question. I'm testing with n=6 animals in 6 different situations. It's repeated measures because all 6 animals did the same tests. When I do the column statistics to see if the distribution ...
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22 views

Friedman's test for a analysis with one between factor and one within factor

Friedman's test is the non-parametirc version of a mixed design ANOVA (with one between subject and one within the subject) or ANOVA (repeated measures) with just a within-subject design?
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20 views

Friedman test when subjects are not a random sample from a population/ when subjects are dependent

Imagine that you measure all $n$ people from a school class in $k$ $\geq2$ different treatment conditions. My goal is to find out whether the there is a systematic difference in Ranks (i.e. the $H_0$ ...
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44 views

Compare 2 classifiers on 2 datasets using F1-score

I am doing a little research in the field of multiclass imbalanced data classification. It entails comparing multiple "base" classifiers on 2 datasets. I followed the well known paper by Demsar and ...
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125 views

Assumptions of the Friedman Rank Test

Let $X_i:= (X_{i,1}, ..., X_{i,k}) $ for $i =1...n$ be $\mathbb{R}^k$-valued random Variables with $k\geq2$. I wonder what the exact assumptions are to apply the Friedman test to Realisations of ...
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286 views

Post hoc test for Friedman test

I am running a Friedman test for my non-Gaussian data, on MATLAB. However, I am confused about the post hoc test to choose. Two concerns: (1) MATLAB's multcompare ...
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78 views

Skillings-Mack test in R

I'm working with some ranging data from GPS collars, and I want to test if there is any difference in distance moved between the GPS positions over the day. My data looks like this (rows = days): I ...
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35 views

What comparative analysis can I use for rank ordered data, divided into two groups, from a survey questionnaire?

I have a dataset from a survey questionnaire. Let's say I can divide the participants into group A and B based on a screening question. These participants then rank 7 different options in order from ...
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227 views

SPSS's Friedman's Two-Way ANOVA by Ranks: Where do the pairwise comparisons come from?

I'm currently trying to reconstruct a significance analysis that I did years ago (when I knew even less about statistics that I do now). I have the strong feeling that what I did was invalid, and that ...
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20 views

Rates Data Analysis

I'm currently working on incidents data; for each cause I have a rate (nbr incidents divided by the number of car trip aggregated on 1 day for each car). I have this for 4 days. The goal is to check ...
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How can I analyze patterns rank order data across multiple sets of rankings?

I had respondents complete a survey in which they ranked five word definitions based on how important they were for 18 different words. I want to see if there are features, like part of speech, that ...
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19 views

Best way to analyze multiple assessed variables by group

I am dealing with a case, which for me is hard to handle because I am not 100% sure which analysis method to chose. I have a set of 1410 observations (each one a unique person) and a group variable (...
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1answer
230 views

Bonferroni correction for Wilcoxon signed rank test with 6 related samples?

I am comparing scores of the same group of people over 7 days. I first did a Friedman's test to know where the differences were between the 7 days and I did a Wilcoxon signed rank test for the Post ...
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2answers
136 views

Friedman's test or Kruskal-Wallis?

I am investigating the effect of an intervention treatment on a group of samples over 5 time points (a period of 2 months in total) For example: Subject 1 - Timepoint 1 (Dose 1), 2 (Dose 1), 3 (Dose ...
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2answers
189 views

Statistical Test Evaluation?

I want to use a statistical test to show that there is a significant difference between 9 algorithms over 2 datasets. I have read Demsar's paper and used Friedman's test (also used Iman's corrected ...
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66 views

Are weighted Friedman tests possible?

Is it possible to conduct a weighted Freidman test? Say I want to know which of three foods taste better to potential diners. So I present 10 experts with each of the three foods (assume order is ...
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100 views

Kappa vs Non-parametric test for intra-observer data

I am looking at a set of data which I analysed blinded (n=10) at two separate sittings. I am trying to show that there is intra-observer agreement (my measurements are repeatable and reliable). My ...
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2answers
56 views

Test to compare questions in survey

I couldn't find this situation described somewhere, though I think it's pretty common so I post it here. I have data from survey that is asking repondents to evaluate their color preferences across ...
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2answers
422 views

Friedman test and Wilcoxon

I recently conducted research where I have chosen the Friedman nonparametric test to check if there are significant differences in dependent variable values obtained on 4 different occasions. I find ...
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95 views

Test for the comparison of multiple paired samples

I have a set of patients where radiographs from the neck were taken at different locations (1,2,3) from the left and from the right side. These radiographs were then scored using an ordinal scale. The ...
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67 views

Repeated measure with with unequal group variance - Friedman Test?

I have a small, but untidy, dataset. I think I should to use non-parametric tests, but I want to check my understanding since I have not often used non-parametric tests. My dataset is from a small ...
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359 views

How must the null hypothesis be rejected for Nemenyi test to be allowed?

Suppose we have algorithms $A_k$ and $B_k$, $1\leq k\leq n$, and $\alpha = 0.05$. Friedman test for the algorithms $A_k$ shows that the null hypothesis that all $A_k$s perform equally well, can be ...
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133 views

Dealing with non-significant results in the Wilcoxon signed rank test

A little background: I'm trying to create a weighted formula for artists telling me how good they are based on the ratings I assign them for different characteristics they have. Basically I'm going ...
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3answers
4k views

Friedman test and post-hoc test for Python

In my dataset, I have five (ordinal) groups with an x-amount of measurement. Because homoscedasticity is violated, I performed the Friedman chi-square test to see if there are any statistical ...
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105 views

Alternative to Friedman's?

I have ordinal data (from Likert scores) that are not normally distributed and is paired,there are more than 3 tests over time. There will be something in the region of 150 people evaluated. How do I ...
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24 views

Survey on how frequently a group use a particular device: Which analysis methods?

I surveyed a group of photographers and asked them how frequently they used a particular type of lens for a specific type of photograph. I now want to find out which lens or lenses are the most ...
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426 views

What non parametric test? multiple dependent variables, between subject variable, and a within subject variable

I'm hoping for some advice re non-parametric stats: I've measured various parameters in three different groups (G1, G2, G3), each with a different disability. Each of the measures were made on three ...
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1answer
1k views

Which within-subject non-parametric test?

I have to do a non-parametric test on data because the distribution is not normal. The data is about the effectiveness of 2 different Aphasia therapies. There are 54 Aphasia patients tested before ...
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41 views

Can I use the Kruskal-Wallis test for measures on the same animal before and after a treatment has been applied

In my experiment I have 3 treatment groups. Behaviours are scored for each subject (while they are isolated) before and after the treatment is applied. I thought that the Kruskal-Wallis test could ...
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1answer
1k views

Can Friedman's test be used with two samples?

When talking about Friedman's test, it commonly comes accompanied by a whole name of "The Friedman's test for three or more correlated samples". The question is, could results be valid if I apply ...
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1answer
51 views

Is my hypothesis testing approach correct?

I have one dataset which was tested under different programming languages / versions of the same algorithm. I consider them to be the treatments. I want to test the effect of the treatments, so I ...
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1answer
331 views

Is Friedman's test for dependent samples or not?

Which test should I use for hypothesis testing on more than two dependent non-parametric data? The Friedman's test seems to be the option, as I have read in several books and webs, but, when I look ...
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81 views

Many-to-one post-hoc comparisons after Friedman test

Is there any established technique (something like the Dunnet test) for performing many-to-one post-hoc comparisons after the Friedman rank test for repeated measures? I would be also very grateful ...
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1answer
45 views

Is my data ordinal?

I am comparing three groups of participants, who gave ratings during a certain test on a scale from $1$ to $4$ (with $0.25$ steps). I was planning to do an ANOVA, but realized that a thing such as the ...
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0answers
62 views

Relationship between medication and severity of symptoms

I'm looking to determine whether there is a relationship between the type of medication used by an individual and their self-reported severity of symptoms. Independent Variable: Medication Type (...
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0answers
73 views

Comparing multiple items measured with ordinal scale

I have 20 items measured with 7 point ordinal scale by roughly 200 of respondents such that every item's relative importance was assessed by every respondent. Item example: What is the importance of ...
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0answers
678 views

How to compute effect size for Friedman's test?

I was looking for a way to compute the effect size for Friedman's test, but could not find any reference. I wanted to see if there is any difference between the groups and what its size was. I have ...
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1answer
4k views

Why run a post hoc wilcoxon signed rank test after Friedman test, why not just skip to Wilcoxon sign test instead?

I understand that one is required to run post hoc tests after the Friedman test. For example, while the Friedman test may find a statistically significant change amongst 3 treatments, one may follow ...
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1answer
90 views

Equivalence of formulations for Friedman Test?

I'm trying to implement a Friedman test, and came across two sites giving methods for its implementation, namely, Wikipedia (perma-linking for posterity) and the NIST. At first glance, the general ...
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1answer
67 views

Nonparametric 2-way ANOVA for data with unequal n's due to possibly informative missingness

So my problem revolves around trying to find the right test for my data in R. I've been doing an experiment that is measuring sublethal effects in a toxic environment, and as a result, even though I ...
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163 views

Repeated-measures ANOVA vs. Friedman-Test (normality?)

I've four (paired) datasets consisting of 43 rows and want to check if there is statistically significant change between those groups. To see whether a repeated-measure anova or it's non-parametric ...