# Questions tagged [permutation]

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• 211
1 vote
73 views

### Permutation Test for mean ratio

I am given three vectors of length 11, that represent blood levels of a hormone measured after placebo, old and new treatment. ...
• 11
138 views

### How do you use numPerms to get the total number of unique permutations for a PERMANOVA?

I am trying to calculate the number of unique permutations for a PERMANOVA using the R adonis2 function but I am getting stuck on defining my permutation scheme. As ...
1 vote
234 views

### Advantage and disadvantage of Wilcoxon rank sum test compared to permutation test [closed]

What is the advantage and disadvantages of Wilcoxon rank sum test compared to permutation test? I want to know at least one each based on the shape of distribution of raw data.
• 11
169 views

### Question about how to think of the binomial distribution with a combination vs a permutation

I know there are many questions on why use a combination formula over a permutation formula for the binomial distribution ( for example here), but looking through multiple of these, I still don't ...
• 681
1 vote
60 views

### if a feature appears as the most important among a variety of models, does that make this feature empirically important?

Lets say that I train a variety of different models - SVM, XGBoost, LogisticRegression, Random Forest, KNeighbors, etc. I then take the permutation importance of each model, and find that ...
45 views

### Populating an even distribution of values across multiple axis?

I'm trying to design an experiment with: x number of people y number of tasks z number of ...
• 101
286 views

### How many ways can you arrange the digits: {1,2,2}, so that the resulting number would be even?

To quote the whole question accurately: Various 3 digit numbers can be formed by permitting the digits 122. All arrangements are equally likely. Given that any resulting number is even, in how many ...
1 vote
257 views

### Calculate a permutation-based p-value for a risk ratio

Summary How do you calculate a two-sided p-value for a risk ratio/relative risk (obtained from a GEE logistic regression via predicting risks with and without a treatment) based on a permutation test, ...
99 views

### sampling distribution of a test statistic when doing permutation test

In a permutation test, we have a test statistic $T$ (for example t-test, f-test, etc.) that is applied to the original data to obtain an observed value $o_{obs}$ for the test statistic. Next, the data ...
23 views

### How to order individuals within groups where group order must remain the same [closed]

I am attempting to get every ordered combination of individuals in groups while keeping the order of the groups consistent. For example, there are four individuals in group 1, two individuals in group ...
270 views

### What is the chance all choices are different?

Suppose everyone (7 people) chooses independently and randomly out of 7 choices. What are the odds that no two people have picked the same option? I feel like the answer is $5040/823543,$ but I am ...
• 43
227 views

### How to understand embedding dimension in permutation entropy when checking predictabilty in electric load data?

I am predicting electric load data with different deep learning models and I am trying to define the predictability of the data. So far I came across the permutation entropy (PE) as a measurement for ...
• 131
494 views

### effect size for pairwise permutation

I am reading a paper that is using permutations to compare the means of two different treatment groups (a nutrition study, took minimum - maximum) that have low sample sizes, and so the groups are ...
• 13
102 views

### Random samples within the Central Limit Theorem - why select with permutation with repetition?

"The central limit theorem states that if you have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the ...
• 119
44 views

### Given 9 coat hangers (3 groups), what's the probability

If I had 9 coat hangers (for example: 4 green, 3 blue and 2 red), what would be the probability of the first four being [green, green, blue, blue], if I just chuck the coat hangers into the wardrobe ...
199 views

### Disagreement regarding the role of permutation/randomization/shuffling in permuation testing between two populations

A colleague and I recently got into a conversation/disagreement regarding permutation testing (e.g. for comparing the mean value of two populations). While i thought i had a fairly good understanding ...
965 views

### Post-hoc test of two-way permutation ANOVA

I have a 2x2 study design to test the interaction between two drugs, with a single variable outcome. The data are very much non-parametric and it seems that a good alternative to the traditional two-...
• 21
1 vote
63 views

### How to correctly apply a PERMANOVA to a half-crossed experimental design

I'm a biologist and conducted an experiment in which I took analytical samples of aphid infested plants and analyzed them using metabolomics. The plants were chosen based on their Genotype (...
• 21
74 views

### Can I use a permutation test to test the null hypothesis ''The difference between two groups is X''?

From what I read on permutation test, the null hypothesis is usually that there is no difference between the two groups. I want to test if the difference between the mean of the two groups is $\theta$ ...
1 vote
34 views

### How many ways to order such that one group comes first?

This question arose while playing a board game that uses cards. Imagine we have 11 cards total. 3 are red (R), 1 is blue (B), and 7 are yellow (Y). How many ways can we randomly order the 11 cards so ...
• 238
331 views

### Schitt’s Creek David Ring Combination

So I’ve been trying to figure this one out. On Schitt’s Creek, David wears various combinations of rings. He has four rings and he can arrange them on his ten fingers in various ways - each ring is ...
367 views

### Quantitative/statistical comparison of two orderings/permutations

There is a couple, say, Theresa and Robert. They assess their preferences on 5 books by ranking them from the most attractive to the least one. Theresa: [0,4,3,2,1]...
• 2,856
40 views

### Probability of n persons picking multiple numbers from N numbers, that all choices are different

Given $N$ distinct numbers, $n$ persons each picks $x_i > 0$ numbers, what is the probability $P$ of them all picking different numbers? The limiting case of $n > N$ is trivial, $P = 0$. Same ...
• 133
51 views

### Intuition behind permutations + probability

I'm new to stats so I'm struggling to grasp the intuition behind permutations + probability. Would anybody be able to help me with parts (b) and (c) of this question? Any help is greatly appreciated :)...
71 views

### What does it mean to "permute" a predictor in the context of random forest?

I am reading the vignette for the R package randomForestExplainer. There the result accuracy_decrease (classification) is defined as mean decrease of prediction ...
• 2,291
43 views

### Permutations - counting [closed]

Four girls bought each a swimsuit , and they decided to share them . How many days are needed so that each girl will wear each swimsuit once ?
14 views

### One sample data with unusual structure, permutation test?

I have N sets, each of them consisting of 1000 integer values. Typically, more than 90 % of values within a set is zero, thus median is zero. The nonzero elements are positive integers. We take N ...
437 views

### One sample permutation test on skewed data

I have one sample of values, each of them is a z-score from mutually independent z-scored distributions. I aimed at testing that the mean value of the sample is larger than zero. Originally I wanted ...
13 views

### Distribution of a rate in a subsample after permutation of the total dataset

I need to estimate the distribution of a rate in a subsample after permutation of the total dataset. I was wondering whether it's sufficient to use the binomial distribution with the global rate ...
• 2,929
79 views

### Evaluate clustering accuracy based on an adjacency/similarity/connection matrix

Description In the classification tasks, the classification accuracy is computed by accuracy=n_correct/n_total For example, if I have three samples, and the ...
• 11
1 vote
265 views

### Interpretation of the adjusted rand-index

I'm trying to understand the adjusted Rand index for a metric review that I'm doing. I found this question most helpful so far: Calculating the adjusted rand index? https://en.wikipedia.org/wiki/...
• 855
2k views

### Adjusting P values for multiple comparisons using permutation tests

I have a number of continuous predictors (biomarker measurements) which I would like to test for association with a binary outcome variable (disease status), adjusting for multiple comparisons. As ...
• 51
[Hoping that this is the right Stackexchange site; inspired from a true story seen at work] Joe has a measuring instrument and $n$ objects to be measured (say, a scale and $n$ weights). He measures ...