Questions tagged [ties]
Ties refer to equal values observed in the data. When multiple, ties can pose a problem for some methods of data analysis.
52 questions
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Rational way of handling 0s and ties in Wilcoxon Signed Rank Test in the background of my context
In the background of the discussion How to deal with ties when conducting Wilcoxon signed rank test?, I have the following 2 follow up questions:
I have 52 pre and post scores with ties and 0's so I ...
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Wilcoxon Signed rank test for heavily tied paired data
We conducted an experiment to test the effect of a map annotated with the height of landscape features on participant's estimates of height relative to that recorded by a UAV. We asked them to record ...
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How to simulate data with ties in R
I am using R to investigate the effect of tied values on rank-based correlation statistics
I wish to simulate correlated bivariate standard normal data with some specified proportion of tied values (...
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Chance of a tie for most goals in a set of 4 football matches
My statistics knowledge is basic at best but here goes:
4 football/soccer matches with expected goals of 2.6, 2.75, 2.4, 2.85
I'm interested in working out the probability of at least 2 of those games ...
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How to handle ties in pairwise wilcoxon rank-sum test?
I am willing run the wilcoxon rank sum test for different combination of variables, and using the base R code, I get a lot of warnings. The reason is that there are so many (about 30% of the whole ...
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What methods can be used to overcome the tie-breaking when using majority voting in ensemble?
What methods can be used to overcome the tie-breaking when using majority voting in ensemble? I read that Weighted majority voting can help; however, it wasn't effective on the dataset I am using in ...
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Use of Mann-Whitney w/ Ties
I am tracking the results of a test between a control group and 1 variant group. Each group contains (an unequal quantity of) users whose order count we're now tracking. The histogram is heavily ...
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What happen if KNN has k=1 and there are 2 nearest classes with the same distance
What happen if KNN has k=1 and there are 2 nearest classes with the same distance?
as fare as I know, If k is even number and have equal classes number it will random class for the answer.
But what ...
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ties in Wilcoxon t test in R
I have a paired data with a small sample size of 19 subjects who gave different scores at time 1 ($T_1$) and time 2 ($T_2$). I'd like to conduct a Wilcoxon test using R, because my data are not normal....
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Math behind Kendall tau-b
I was looking up the definition of Kendall's tau-b and noticed that there seems to be two distinct equations floating around:
Equation 1 (Wikipedia):
$ \tau_b = \dfrac{n_c - n_d}{\sqrt{ (n_0 - \sum ...
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Kolmogorov-Smirov two sample test, ties -- will adding random noise fix the problem?
There are a lot of questions on this site about warning for "ties" in the Kolmogorov-Smirnov test. Here are a few of those questions.
Is there an alternative to the Kolmogorov-Smirnov test ...
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Cox Model - Are Censored Observations in the Risk Set?
I'm running a cox proportional hazards model. I'm somewhat new to the area and have a question about the definition of the risk set and the use of it in computing partial likelihoods.
Specifically, ...
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How does one apply hierarchical agglomerative clustering when multiple positions are equidistant (non-unique distance matrix)?
I have been following this single/minimum -linkage example to better understand hierarchical agglomerative clustering. I noticed that the entries of d_ij are unique ...
user223366
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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 ...
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Ties in a two-sample Kolmgorov-Smirnov test
This question is somehow connected to this one.
I am performing a two-sample KS test in R and I think I have not fully understood the issue of the ties.
Reading the help: ...
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Is a kernel density estimate meaningful if > 25% of my data are duplicates?
The title pretty much says it all. I have data that consists of 80 samples but there are always at least four samples that have exactly the same value. I want to assess, whether the data is unimodal. ...
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Distribution that minimises ties
Here's a result I'm trying to get as part of a larger problem I'm solving: The random variables $A_1,B_1...J_1$ and $A_2,B_2,...J_2$ can take integer values between 0 and 100 such that $A_1+...+J_1=...
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Methods for handling ties in survival analysis
I am aware that there are different methods to deal with ties in survival analysis, which are based on alternating the partial likelihood used to estimate the beta parameters. I am working on a ...
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Kendall tau for data with many ties
I am working on an an application that is part managed code and part unmanaged code. Because of the unmanaged code part, there was a requirement in the specifications that states that memory usage ...
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What are the accepted amount of tied ranks in your dataset when using the rank product statistic?
I'm currently trying to use the rank product statistic on very large datasets but I'm finding that a lot of the entries in my data end up receiving the same rank. To break these ties, I'm randomly ...
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Proving that the fit for a regression problem with tied input values can be obtained with reduced weighted least squares
This problem is from Elements of Statistical Learning, exercise 2.6
The problem states:
Consider a regression problem with inputs $x_i$ and outputs $y_i$ and a parameterized model $f_\theta(x)$ to ...
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Stochastic gradient descent for neural networks with tied weights
For the neural network depicted below, I want to calculate the Error with respect to $w_{tied}$, which we get if we tie the weights $w_1$ and $w_4$ together. Tying the weights together would help to ...
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Wilcoxon Signed Rank test and reporting ties
In writing up results for a Wilcoxon Signed-Rank test, do you have to state if there were no ties in the data?
Also, should the Z statistic be reported if the sample size is < 20 ?
Thanks!
user163019
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Exact Null Distribution with Ties
I am interested in deriving exact null distributions for small-sample test statistics with non-trivial ties. Not fundamentally continuous variables that happen to have a few repeated values, but ...
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Kendall’s tau-b version calculation steps with tied ranks
I am trying to calculate Kendall’s tau coefficient for example given by Scipy in python. It is for tied ranks with tau-b version. The tau should be -0.47140452079103173 but I get a different result. I ...
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Slight inconsistency between the Kruskal-Wallis built-in R function and manual calculation
I'm confused by the following, and I haven't been able to dig up the answer elsewhere.
I'm trying to learn R while doing some statistics, and, as an exercise, I try to double-check the results of ...
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Tied rank correction formula vs fractional ranking in Spearman's Rank Correlation
I have found two ways to deal with ties when calculation Spearman's Rank Correlation.
Calculate the ranks using fractional ranking, then calculate the Pearson's correlation of the ranks.
Calculate ...
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Autoencoders' gradient when using tied weights
In autoencoders when using tied weights, it was mentioned the gradient with respect to w is the sum of two weights. I didn't understand this, can someone elucidate this.
it is mentioned here on slide ...
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Different methods for finding spearman's coefficient produce diff p-values depending on presence of tied values
I'm hoping someone can shed some light on the discrepancy between the p-values obtained from two different functions in R for conducting a spearman's test. The two tests produce the same p-values in ...
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"Ties should not be present" in one-sample Kolmgorov-Smirnov test in R
I am going to use the Kolmogorov-Smirnov test to test normality of MYDATA in R. This is an example of what I do
ks.test(MYDATA,"pnorm",mean(MYDATA),sd(MYDATA))
...
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Understanding Kolmogorov-Smirnov test in R
I'm trying to understand the output of the Kolmogorov-Smirnov test function (two samples, two sided).
Here is a simple test.
...
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Autoencoder with tied weights: bias?
For some unsupervised learning problem, I need to train an autoencoder, so that I only have to store the encoder afterwards. However, I am not sure on how and if the bias weights can be tied.
To make ...
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Kruskal-Wallis: how to handle ties that might not be really ties?
I have data from a mass spectrometer that are precise to 6 decimal places and range from 0.1 to 10. However, some items cannot be measured by the mass spectrometer because they are "below the limit of ...
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adjusting ties for kruskal.wallis
I would like to compare the means of three groups using the Kruskal Wallis test in R.
My data looks like this:
...
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Understanding warning message "Ties are present" in Kruskal-Wallis post hoc
I'm running post-hoc comparisons after a Kruskal-Wallis test. I'm using the PMCMR package.
...
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Kolmogorov-Smirnov vs Mann-Whitney U When There Are Ties
I have a dataset consisting of rank data, some 100 cases and 2 groups. (The 2 groups contain about 1/3 and 2/3 of the cases.) I would like to test whether the two groups differ with respect to median ...
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ks.test and ks.boot - exact p-values and ties
I am confused by the behaviour of ks.test (package stat) a) in the presence of ties and b) if one-sided while doing a two-sample test. Documentation: "Exact p-values are not available for the two-...
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How to estimate Savage scores of tied ranks
I want to calculate the Top-Down Concordance coefficient that quantifies the agreement between two rankings by emphasizing more on the lowest rankings. The original paper is:
R.L. Iman and W.J. ...
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compare binary responses with ties
Suppose I am testing two drugs, I and II. The response profile is either I > II, I < II or I = II. I was trying to figure out if I is in fact better than II.
One way I thought of was to throw out ...
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Nelson-Aalen estimator and interval censoring/tied events
I just noticed that the Nelson-Aalen estimate of the cumulative hazard changes depends on the existence of tied events. As a toy example, consider a study with 3 patients. The patients die on day 1, 5,...
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Dealing with ties, weights and voting in kNN
I am programming a kNN algorithm and would like to know the following:
Tie-breaks:
What happens if there is no clear winner in the majority voting? E.g. all k nearest neighbors are from different ...
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Mann-Whitney test with ties
I have two data sets with PDFs roughly like this:
$$
p(x) = \left\{
\begin{array}{lr}
.75 & x = 0\\
\text{Lomax}(x) & x > 0
\end{array}
\right.
$$
i.e. it's ...
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Is there an alternative to the Kolmogorov-Smirnov test for tied data with correction?
I've got a bunch of data from two samples (control and treated), each containing several thousand values which are to undergo significance testing in R. Theoretically, the values should be continuous, ...
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How does ties.method argument of R's rank function work?
I am using rank(a, ties.method="max") to rank a. But I am not quite sure what does ties.method="max" do. Can you please help?
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Cluster analysis with ties issue
When I perform cluster analysis in SAS, the SAS log sometimes return a warning something like this:
...
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Ties in the data
Are there any "good" ways to eliminate the effects of ties in a data set for statistical analysis? For example, in finding the correlation between two series which has lots of ties?
I would like to ...
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Why are ties so difficult in nonparametric statistics?
My nonparametric text, Practical Nonparametric Statistics, often gives clean formulas for expectations, variances, test statistics, and the like, but includes the caveat that this only works if we ...
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Is it wrong to jitter before performing Wilcoxon test?
I wrote a script tests the data using the wilcox.test, but when I got the results, all the p-values where equal to 1.
I read in some websites that you could use ...
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What to do about ties in voting results?
Imagine a committee of people in charge of hiring a CEO. A committee member can vote "No hire" (+0), "Maybe"(+1), "Hire"(+2) for a potential CEO candidate. Each CEO is scored based on the votes, and ...
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Survival analysis: continuous vs discrete time
I am confused about how to decide whether to treat time as continuous or discrete in survival analysis. Specifically, I want to use survival analysis to identify child- and household-level variables ...
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