Questions tagged [permutation]
The permutation tag has no usage guidance.
50
questions
1
vote
1
answer
42
views
Question on permutation and combination
I am having a trouble understanding how to answer the following question and what method to use. The final answer is $415800$
Suppose there are 4 committees A, B, C, and D. 11 candidates are
randomly ...
- 11
0
votes
0
answers
15
views
General interpretations of permutation null distributions under the alternative
I've come across some papers employing z-scores of permutation null distributions as a primary metric in neuroscience (for an example, see here).
The authors computed a coefficient of interest in a ...
- 1
1
vote
0
answers
18
views
How to evaluate whether a treatment effect is significant given variance in measurement
I have two samples I am using to evaluate the effect of a treatment. Group $T$ contains 60 treated objects and their scores and group $C$ contains 60 control objects and their scores. The two groups ...
- 65
1
vote
0
answers
63
views
Making sense of the performance measures offered in Ranger
I have trained a regression forest using the R package ranger. Now I would like to discuss the variable importance measures of the included features. However, I am having difficulties understanding ...
- 39
0
votes
0
answers
14
views
Number of possible permutations for N groups from I items where each item is of a different size but group total is fixed across groups
this is my first post.
I am not sure how to approach this problem, I would like direction or even an algebraic solution please.
I have to sort 70 different sized items out into 12 groups.
Each group ...
1
vote
0
answers
97
views
Is this a valid statement according to the de Finetti theorem?
Some background on my problem - Let us consider a discrete memoryless channel (DMC) $W_{Y|X}$ from Alice to Bob. A DMC is a conditional probability distribution over the random variable $Y$ given ...
- 116
1
vote
1
answer
44
views
Bootstrapping or permuting as resampling methods for correlations?
I have many variables ( ~2000 and 320 samples) and I have found the correlation coefficient for each unqiue pair of these variables through Spearmann (underlying data does not have normal distribution)...
- 43
0
votes
0
answers
28
views
Clarification of one sided vs two sided p value following permutation testing
I am unsure as to how to compute a two sided p value following permutation testing, following different examples online.
For example, this post Two-sided permutation test vs. two one-sided, gets the ...
- 43
1
vote
1
answer
120
views
What's the difference between a Permutation and a Perturbation?
I frequently come across the terms Permutation and Perturbation within the field of explainable AI.
I understand that both terms refer to methods that make changes to a sample's features. However, I'm ...
- 349
0
votes
1
answer
38
views
Number of ways you sit next to your friend with 4 other people at a round table [closed]
This is a question I have after seeing Q1 of this question. There are a total of 6 people including you and your friend, and you guys are about to sit at a round table. The method of counting the ...
- 231
1
vote
0
answers
34
views
Permutation and order statistic
Let $X_1,…,X_n$ be i.i.d. random variables. Are these two equalities correct?
$P[X_{(2)}<x_2,…,X_{(n)}<x_n| X_{(1)}=x_1]=\\
=n!P[X_{2}<x_2,…,X_{n}<x_n| X_{1}=x_1]=\\
=n! P[X_{2}<x_2]…P[...
- 201
1
vote
0
answers
54
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
2
votes
1
answer
108
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 ...
- 41
1
vote
0
answers
146
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
0
votes
0
answers
40
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 ...
- 601
1
vote
1
answer
57
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 ...
0
votes
0
answers
24
views
couldn't feature importance be used as the intrinsic predictive power of that feature, if the model has 99.99% accuracy?
Ok so here is the scenario I've been thinking about: feature (permutation) importance measures the importance that a feature has in helping ONE PARTICULAR MODEL correctly classify targets.
Let's say ...
0
votes
0
answers
36
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
0
votes
1
answer
156
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
1
answer
132
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, ...
- 32
0
votes
0
answers
49
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 ...
0
votes
1
answer
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 ...
4
votes
3
answers
191
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
1
vote
0
answers
125
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 ...
- 121
0
votes
1
answer
223
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
0
votes
1
answer
80
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 ...
- 99
0
votes
2
answers
37
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 ...
- 5
0
votes
2
answers
132
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 ...
2
votes
1
answer
560
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
0
answers
34
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
2
votes
1
answer
67
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 $\theta$ ...
- 21
0
votes
1
answer
29
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 ...
- 143
0
votes
0
answers
181
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 ...
0
votes
1
answer
128
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]...
- 2,638
3
votes
1
answer
37
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
0
votes
1
answer
45
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 :)...
- 3
3
votes
1
answer
66
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 ...
- 1,928
-2
votes
1
answer
40
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 ?
0
votes
0
answers
13
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 ...
0
votes
1
answer
330
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 ...
0
votes
0
answers
10
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 ...
- 2,533
-1
votes
1
answer
74
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
0
answers
191
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/...
- 825
3
votes
1
answer
940
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 ...
- 31
18
votes
3
answers
1k
views
Finding most likely permutation
[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 ...
- 291
1
vote
1
answer
200
views
Probability that Secret Santa arrangement for couples will result in perfect pairings
4 couples, 8 people total, participate in a Secret Santa gift exchange. Call the people A, B, C, D, E, F, G, H. Assume A+B are a married couple. Likewise, assume C+D, E+F, and G+H are all couples. All ...
- 2,357
2
votes
2
answers
146
views
Probability that Secret Santa arrangement will result in perfect pairings for couples
4 couples, 8 people total, participate in a Secret Santa gift exchange. Call the people A, B, C, D, E, F, G, H. Assume A+B are a married couple. Likewise, assume C+D, E+F, and G+H are all couples. ...
- 2,357
0
votes
0
answers
91
views
Equal probability of random permutations
For $n$ distinct elements $x_1, x_2, .., x_n$. If we generate a random permutation $\pi$ of length n (so of all elements), how to prove that for every $i$th element $\pi_i$ of it, the probability $P(\...
- 113
2
votes
1
answer
138
views
All combinations for a King and Queen (coed) 2's Tournament Pool Sheet (N girls and N guys)
Ok so I have N girls and N guys. I need to create a 2's beach volleyball coed tournament (also known as King and Queen style). I want a list (like Joe and Jill versus Donald and Melania...etc.) of all ...
- 121
7
votes
1
answer
585
views
Probabilities arising from permutations
Certain interesting probability functions can arise from permutations. For example, permutations that are sorted or permutations that form a cycle.
Inspired by the so-called von Neumann schema given ...
- 1,174