Questions tagged [wilcoxon-signed-rank]

Wilcoxon signed-rank test is a non-parametric rank test to compare two paired samples, whether values in one are bigger than in the other. Can also be used to compare one sample to a fixed value. [The test NOT to be confused with the sign-test].

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Hypothesis testing with regression models

I have two regression models: a linear model with one variable, and a neural network with many. I want to test whether the neural network is better than the linear model. I am wondering the best way ...
46 views

How to merge multiple one-sample Wilcoxon-tests into single test/model

I have data on the monthly rent of a certain group of people (n = 10 people). We call them people X. These people live in different neighborhoods (very far apart). Furthermore, I have data on the ...
19 views

Wilcoxon signed rank with multiple repetition

How could I do Wilcoxon signed-rank statistical significance test with multiple replications in python or other languages? (since python does not have any parameter as the input of the function for ...
71 views

Analyzing ABn test when normality is not met

I'm analyzing an unpaired A/B/C/D test to assess whether the mean or median of population B/C/D is higher than the one of A. As shown from the left plot the normality distribution cannot be assumed. ...
36 views

paired test VS unpaired test

I have a set of paired measurements which were collected before and after some trigger for a set of users. Users can react differently to trigger, i.e for some measurements before trigger are larger ...
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Treatment of Ties in sign test (paired-samples sign test)

I'm curious about the validity of removing/ignoring ties when calculating the p-value for the sign test. By ties I mean ($x_{before} = x_{after}$, where $x$ represents the measurement). According ...
23 views

What Wilcoxon Test is appropriate for paired categorical data?

There is currently a story in the news in the UK about negative effects of puberty blockers in children: 'It showed that after a year on puberty blockers, there was a significant increase found in ...
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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 ...
52 views

Test for multiple samples of ordinal data

I have 10 independent samples of ordinal data ranked 1-3. I also have predicted ranks for the same data set. I want to test if the predicted ranking matches the observed ranking at a rate better ...
72 views

Kolmogorov-Smirnov test vs. Wilcoxon signed-rank test for two samples

I would like to ask a question about the usage of Kolmogorov-Smirnov test and Wilcoxon signed-rank test to show that two samples have the same distribution (specifically, log-normal). Specifically, I ...
279 views

Wilcoxon signed rank test – critical value for n>50

I have seen that someone has asked a similar question a few years ago, but unfortunately the answer is not helpful. I am in the process of estimating a Wilcoxon signed rank test with a n=63 by hand. ...
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Compare change of ordinal variables between admission and dismission with different levels

I would like to compare difference between admission and dismission fron rehab center of an ordinal variable relative to diagnosis. At admission patients are divided in 3 groups (Emersion, SMC or SV, ...
20 views

Wilcoxon signed rank test?

I would appreciate any advice possible. I am doing a study to look at change in value of my markers before and after a device change. My data is non-normal. I need to see how the value changes from ...
52 views

In R (nlme/lme4), how do I compare two linear models with different sample sizes and different groups? [duplicate]

First off, I have a dataset with sparse longitudinal data. There are 30 individuals with 1 sample, 30 individuals with 2 samples, and 5 individuals with 3 samples. Various categorical variables are ...
36 views

Statistical test for rubric-scored student responses

I am generally a qualitative researcher, but in my current study I am asking a research question that requires (very little, but some) quantitative tools. Simplistically, I have scored students' ...
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mutation difference

I am hematology/oncology physician. i am doing project in CNS lymphoma. i have a question about the best method to calculate if there is any statistical difference in mutation frequencies between 2 ...
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Potential problem in using paired t-test or Wilcoxon if the two samples consist of multiple draws from same group?

I have an experiment that works loosely works as follows: There are ten subjects in each treatment. There are two treatments, A and B. Each treatment has 8 rounds. In each round, each subject is ...
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Comparing the performance of two algorithms with Wilcoxon Signed-Rank Test

I have two algorithms A and B which have to compute a solution to some problem. Each solution is given some objective value ...
39 views

Wilcoxon signed rank test - interpretation

I have 6 dependent variables that were measured on a 5 point Likert scale (treated as interval here). I want to test if their means differ significantly from the midpoint 3. As the normality ...
51 views

Is my interpretation for Wilcoxon Signed Rank test correct?

I ran a wilcoxon signed rank test on paired samples where the outcome variable was a test score. The samples were paired by as siblings (younger and older sibling). I have a problem interpreting the ...
38 views

How does Normal approximation work when ties exist for Wilcoxon Signed rank test?

I ran wilcox.test() in R (outcome variable was a test score and the data was paired samples) and got a warning message saying that it cannot generate a p-value for tied values. I saw the R document ...
64 views

Pseudo median from Wilcoxon signed rank test larger than sample median?

I am left wondering, why I can be in a situation where the pseudo median (population estimator) of a Wilcoxon signed rank test, can be larger than the simple differences between sample medians? I am ...
163 views

Paired or unpaired t-test and Wilcoxon signed rank test?

I am having a conceptual problem, of not being able to grasp whether my data is paired or unpaired. I have to test for the mean and median differences between two sets of data: SBP and GICS (see ...
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Wilcoxon rank signed test, paired or non-paired test?

I have been trying to figure out, whether or not I should use a paired or a non-paired test. My question comes from the fact, that I am trying to get the pseudo median, in order to say that SBP is [x] ...
108 views

Wilcoxon signed rank test - help on interpretation of pseudo median

I am performing a Wilcoxon signed rank test in R, for two paired samples, where I have used the following: ...
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Wilcoxon signed rank test, getting a numerical media difference instead of p-value?

I have been running the Wilcoxon signed rank test, where my output is a p-value. Now, the p-value interpretation I am confident in, but I read in a paper that the authors reported the: The Wilcoxon ...
60 views

Bonferroni for Wilcoxon signed rank?

I conducted a survey that asked participants to rate their level of agreement on a 5 point Likert scale with nine items (1=strongly agree, 5=strongly disagree). Hence, a mean score of 3 would mean ...
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Paired samples with various ordering in observations, signed rank test?

I have a small number (10) of samples to analyze The idea is to measure the impact of two surgical procedures, A and B. In my population, I have people who did first A, and then B, and other people ...
38 views

Wilcoxon - one sample abnormal stock returns

I got a dataset with abnormal stock returns for around 400 securities and i need to find out if they're statistically different from zero. They don't follow a normal distribution, so i would like to ...
78 views

Wilcoxon signed-rank test for paired and repeated measures data

I have a dataset with 45 participants, each with 1-7 datapoints/observations (126 total observations). Each of these observations represents a window of time in which two different methods attempt to ...
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Paired Wilcoxon signed rank test-compare median

I have been comparing driving behavior before and after a technological intervention for a specific group of people. My data is far from normal hence I have used paired Wilcoxon signed rank test. If ...
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Can a Wilcoxon signed rank test be applied on dated data?

I have data for military male and female orders for types of clothing purchased from 2012 to 2018 (below is a very simple example - most of the data is one item purchases). If I look at one type of ...
142 views

P-Values in Wilcoxon test

I have a question that if a p value less than 0.05 in wilcox test means that the two data are significantly different and the p-value of 1 means that are exactly same, then what is the meaning of a p-...
134 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 ...
98 views

How do you perform Wilcoxon matched-pair sign-rank test in Stata using a grouping variable? [closed]

I'm performing a diagnostic method comparison study in which I have 2 groups; one assessed using the experimental method, and one assessed using the standard method. These groups are matched, with 3 ...
52 views

Violating the assumptions of one sample t-test and wilcoxon's sign test

As far as the background of my research is concerned, I developed a framework for sustainability management in organizations through a systematic review of literature and sustainability reports. That ...
26 views

Comparing changes in pre-post count results for two cohorts

Thanks in advance! I have a pre-post analysis Of cases and controls. The outcome variables of interest are emergency room visits and hospitalization visits - both rare occurrences with median = 0 ...
56 views

How to run Friedman test correctly across three sets of questionnaire data divided into sub-groups?

I am trying to evaluate the usability of three prototypes of an application and want to see if there is a significant difference in terms of usability. For this I have collected responses from users ...
25 views

Post hoc for wilcoxon multiple tests

I have a database of brain MRI acquisitions of 20 subjects at two time points. I have elaborated the signal with multiple models. For each model, I have estimated 4-6 parameters maps. At the moment I ...
45 views

Different results from wilcoxsign_test - which test to use?

I am running a wilcoxsign_test from the coin-package and I get different results depending on whether I split my data or not. My data is a data.frame with 3 columns: "Proband", "Treatment", "Mdev". ...
35 views

How to remove pair-wise comparisons that are affected by a batch covariate in pairwise Wilcoxon test

I have a dependent variable that is grouped by an independent.variable (with 3 factor levels) and I want to calculate pairwise comparisons between the groups of the independent.variable. However, I ...
65 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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Imposing orders on distributions based on Wilcoxon test

I am trying to figure out part of a text I am reading about non parametric tests. In there it is stated that: The fact that the output of a rank test is driven by the probability that a value ...
166 views

Wilcoxon Signed Rank Test in Python (Reporting Siegel's T vs W?)

While using the Wilcoxon signed rank test in scypy over a subset of populations, I noticed that my test score was reported as zero for an array of differences whose distribution of medians is heavily ...
392 views

R: coin::wilcoxsign_test() distribution = “exact”

In a repeated measure design, I have two measurements for one variable for N=5 subjects. I am interested in assessing whether the distribution of the differences between the two measurements is ...
48 views

One-tailed test for comparing paired dichotomous responses

Given reference samples $R_i$, I have two dichotomous responses $X_i$ and $Y_i$ I wish to compare. Each dichotomous response (relevant vs. irrelevant to the reference $R_i$) is generated by an ...
155 views

How do I report a Wilcoxon-signed rank test if the medians are the same?

I have data comparing 2 likert-scale answers (1 to 7) where the p<0.05 but the medians are the same. I'm trying to report this in a table. My instinct was to report this similar to a t-test, with ...
591 views

How to graph Wilcoxon test power R

I've been trying to calculate and graph the correspondent power for the wilcoxon signed test and haven't had any luck. I tried simulating two normal distributed samples, apply the wilcoxon test and ...