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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Comparing two groups with non-negative integers?

Can I use Mann Whitney U Test (Wilcoxon Rank Sum Test) to test for differences between two populations for count data (i.e. non-negative integers)?
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Does it make sense to run Wilcoxon rank sum test with sample size of 1 or 2?

suppose I have the following numbers. ...
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Do multiple wilcoxon tests of drug sensitivity between mutated grp and wild-type grp need multiple testing correction?

I am doing wilcoxon-rank-sum tests of the sensitivity (AUC) of over 1000 drugs between mutated gene A and wild-type gene A. So, for each drug, there will be one wilcoxon test and one p-value. Since I ...
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Can someone help with the nuance in the wilcox.test function in R?

This is from a homework assignment for my grad stats class. First I generate a dataset in R: ...
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There is very slight difference but also statistically significant. Could there be a mistake?

In my study to investigate the effect of filter glasses on reading speed and contrast senstivity in albino patients, there is little change in the reading performance level n:61 patients Reading ...
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Which test fits the best here? (oncogenic signalling pathways)

I have a list of patients in rows and oncogenic signalling pathways in columns of two independent matrices One for responders to a drug one for non-responders to the same drugs If a patient gets ...
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Where do Wilcoxon signed rank critical values come from (ie how are they computed)?

Here is the table for Wilcoxon signed rank test critical values, and obviously we can decide whether or not to reject the null hypothesis for a particular scenario based on this table. I understand ...
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Comparing classifiers for multi-label classification predictions

I have a multi-label classification problem (categorical predicted values: A, B, C, D) and I want to test the null hypothesis that there is no significant difference between the classifiers, and the ...
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Is there any possible statistical test for this data?

I have a data set of the daily dosage of a drug that participants take against some signs and symptoms. The data are highly skewed to the left because there are a lot of patients with 0mg per day of ...
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How to combine effect size of Wilcoxon signed rank test

I am doing a Wilcoxon signed rank test on paired samples and it only reports effect size r and p-value. Since I am doing a meta-analysis and have calculated many effect sizes, I want to combine the ...
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Metrics in comparing the rank orders of elements from 2 vectors

I am working on sampling a posterior distribution for parameters in my model using approximate Bayesian computation (ABC). I would like to come up with a summary statistic to compare the similarity/...
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How to get single sample result wilcox_test in R [closed]

I am not a regular R user so I'm struggling a bit on how to get an exact p-value and confidence limits for a single sample using the Wilcoxon Signed-Rank test. wilcox.test does not handle ties so it's ...
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One-Sample Wilcoxon Signed Rank Test when the values are identical

I'm trying to run One-Sample Wilcoxon Signed Rank Test on my data. My data contains 100 values, and I want to compare these values to a standard value. However, all the 100 values and the standard ...
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Using an old trained model on a new data - comparing two populations

I have two populations with the same set of features. The range of the features' values is also the same. I trained Random Forest Algorithm on the first population. Thus, I wonder whether or not I can ...
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One Sample Wilcoxon signed-rank with a negative effect size

Hi i got a Wilcoxon signed-rank done for a one sample t-test because the data failed normality tests. Whilst the result is still significant, the effect size is -0.364. Apparantely it uses the '...
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Comparing similarity of samples under time-dependant noise (KS-test for dependant samples)

I'm measuring response times of a process under different inputs and want to check if the input correlates with the response time. The problem is that the differences I'm expecting are small while ...
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Is a Wilcoxon paired test correct for my case?

We're working with the lovely garden eels: snake-like fishes that live in big colonies, attached to the sandy sea bottom. They feed on plankton and hide in their burrows whenever something big ...
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Test statistics for hypothesis that values in one group always larger than the other group

Assume $x_1, x_2, \dots, x_n$ belong to group $A$ and $y_1, y_2, \dots, y_m$ belong to group $B$. We want to test if values in group $A$ are smaller than values in group $B$ as values in B. I design ...
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Too small sample size for Wilcoxon signed rank test, alternatives?

I have a statistical question about my research. I performed photosynthesis measurements on leaves. I have 6 increasing light intensities, and for every light intensity, I measured the photosynthetic ...
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Student's t-test versus Wilcoxon signed-rank test

Trying to understand when to use which test, am I correct when saying both these tests, test whether two samples could be taken from the same distribution, but the difference is that the student's t-...
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One-sample Wilcoxon test result does not make sense

To evaluate the correctness of a value I have given to something, I have asked a group of people to give a value for it. To evaluate the significance difference between my value with them, I am ...
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Is it appropriate to estimate the mean difference from a Wilcoxon p-value?

I am conducting a meta-analysis involving paired data (two instruments measuring the same thing). Original papers do not provide the standard deviation of the mean difference. One paper provides a p-...
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One-sample versions of the signed rank and rank sum tests?

I wonder if there are applications of the signed rank and rank sum tests in a one-sample context? Signed rank Is there a form of the signed rank test where the difference $A-B$ for each subject is ...
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Can't decide between Paired t-test and Wilcoxon Signed-Rank test?

I'm using data for pre-2020 January-April and the year 2020 January-April (raw data with one datapoint per day, except for the 'pre-2020' category which is the values for one day in 2017, 2018, and ...
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What does it mean if Nemenyi test does not return that the performance of two methods are significantly different while the Wilcoxon test does?

I want to compare the performance of $N$ methods on $m$ datasets. I performed the Friedman test and after that the Nemenyi test. The Nemenyi test is though not powerful enough to conclude that there ...
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nonparametric tests for random forest regression

Ive built a random forest model which predicts temperature, humidity and energy based on 5 inputs. I obtain an R2 value of 0.92, CV(RMSE) of 14, and errors of 3.51%, 4.22%, 7.23% for each variable ...
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Can I use `wilcox_test()` to compar multiple means without `friedman_test()`?

In this example,use friedman_test() first to find significant difference between group,and then use ...
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Friedman test: non-significant post hoc (exact and Nemenyi test) should I run Wilcoxon signed rank tests or Sign tests? Or just accept the results…?

In my data, participants were tested on the same ordinal variable 3 times. In order to test for within-group differences, I ran a Friedman test. After reading this post, I ran the friedmanTest ...
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Wilcoxon Signed-Rank with unequal samples

My apologies if this is a novice question: I am using a 2 tailed Wilcoxon Signed-Rank test to determine if suspension days decrease following a year of PBIS implementation in a middle school. Sample: ...
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Is a statistically significant difference within analytical uncertainty still valid?

The isotopic analyses of two tissues across 50 specimens showed a mean difference of 0.12 ‰. A Wilcoxon signed-rank test for paired samples indicated this to be statistically significant (Z: -2.515, P ...
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Wilcoxon 2-sided test: rejection direction?

I am performing a Wilcoxon signed-rank test on some data, and I would like to show that my experiment A gives better scores than experiment B. I chose a two-sided test as I don't know if A > B or B > ...
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What test is appropriate test for confidence interval for proportion sample (R test)

Seeking appropriate R test approach for small sample. Given 160 units randomly sampled, 140 met the requirements approved living quarters by county standards. If we desire a 90% confidence interval ...
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Comparing two discrete paired datasets

The problem: I am studying the estimated number of cases of malaria in regions of the world and found that both the WHO and IHME have their own estimates. I want to find if the difference between the ...
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How to test right-skewed distribution hypothesis?

Statistics is new to me. My dataset has 7000 incidents that were processed within x number of days. I took a sample of 400 from the population: ...
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Wilcoxon signed rank test for likert data and composite scores

I have a survey where I used seven point Likert scale for all the questions. With 1 being Completely disagree to 7 meaning Completely agree. I wanted to combine multiple questions (let's say 7 of ...
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Non-parametric version of one sample t-test but for multiple groups?

Suppose I have the following experiment set up. I'm trying to build a regression model to predict how much weight a person can bicep curl based on their bicep size. So I go ahead and have a bunch of ...
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Paired t-test on large sample that *should* be normal, but isn't (or Wilcoxon Signed Rank Test)?

A dataset contains the number of fast food restaurants per thousand people for each county in the USA, for two different years (five years apart). 3,143 rows. None of the following are normally ...
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Alternative test

I am doing a peer review. The article is about the effect of yokukansan (YKS) on behavioral and psychological symptoms of Alzheimer disease. There were 15 patients, divided into 2 groups: the ...
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Statistical test for repeated measure data (3x2 contingency table)

This is my dataset Newspaper Internet MN 45 115 IA 20 9 MO 114 56 What statistical test should ...
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How, if ever, is quantile linear mixed model compatible with the signed rank test?

Paired Wilcoxon test evaluates median change rather than difference in medians. Quantile linear mixed model (defined for medians) evaluates change in the medians, rather than median change, as any ...
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Do box-plots fail to visualize Wilcoxon signed-rank tests?

Here someone recommended box-plots for visualization. But the following graph made me realize how box-plots can fail to meaningfully depict the Wilcoxon signed-rank test or sign tests in general: In ...
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Mean difference with paired pre- post- data, don't care about direction of change

I think I've confused myself into a corner. I have a pre- and post- measure, and the change is sometimes +ve and sometimes -ve. I want to see if there's a difference, regardless of sign change. What ...
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Testing mean in dependent non-normal samples

I have time-series data on the multi-level order book for one stock. I want to test whether the mean of the middle spread (bid-ask spread) is different from the mean of the spreads between the ...
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Proper statistical significance tests for small samples of unknown distribution

The title basically says it all; what is considered to be a proper statistical test in the literature for comparing small samples of unknown distribution? That is to say, I run an experiment something ...
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wilcox.test between multiple grouping variables in r [closed]

I have a data set with one numerical variable and 78 binary variables. I know how to perform multiple wilcox.tests between multiple numerical variables against one ...
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Ways to state relationships like “A explains x% the variation in B” but when variation is not present like for non-parametric tests

Example: Income explains 70% of the variance in expenditure. Variation in driving speed can be explained by drivers' age. How does one make such statements if the test used is a non-parametric one? I ...
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What's the appropriate test to be used in this study?

I was asked by an acquaintance of mine for support in interpreting a medical study. I don't work in healthcare, thus of course this was not professional advice. Two groups of people of size $n_1$ and ...
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R removing zeros for pseudomedian and its confidence interval in wilcox.test?

It makes sense to me that we need to remove zeros to calculate the p-value in a Wilcoxon signed rank test. What confuses me is that R seems to leave the zeros deleted when computing the pseudomedian ...
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Why p-values are different

I have a data of total number of mutations and fraction of mutations in each patient for three groups of patients I want to see if these three groups are different in terms of total number of ...

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