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Hauptverfasser: Dalitz, Christoph, Arning, Juliane, Goebbels, Steffen
Format: Preprint
Veröffentlicht: 2023
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Online-Zugang:https://arxiv.org/abs/2312.15496
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author Dalitz, Christoph
Arning, Juliane
Goebbels, Steffen
author_facet Dalitz, Christoph
Arning, Juliane
Goebbels, Steffen
contents Chatterjee's rank correlation coefficient $ξ_n$ is an empirical index for detecting functional dependencies between two variables $X$ and $Y$. It is an estimator for a theoretical quantity $ξ$ that is zero for independence and one if $Y$ is a measurable function of $X$. Based on an equivalent characterization of sorted numbers, we derive an upper bound for $ξ_n$ and suggest a simple normalization aimed at reducing its bias for small sample size $n$. In Monte Carlo simulations of various models, the normalization reduced the bias in all cases. The mean squared error was reduced, too, for values of $ξ$ greater than about 0.4. Moreover, we observed that non-parametric confidence intervals for $ξ$ based on bootstrapping $ξ_n$ in the usual n-out-of-n way have a coverage probability close to zero. This is remedied by an m-out-of-n bootstrap without replacement in combination with our normalization method.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15496
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Simple Bias Reduction for Chatterjee's Correlation
Dalitz, Christoph
Arning, Juliane
Goebbels, Steffen
Methodology
Chatterjee's rank correlation coefficient $ξ_n$ is an empirical index for detecting functional dependencies between two variables $X$ and $Y$. It is an estimator for a theoretical quantity $ξ$ that is zero for independence and one if $Y$ is a measurable function of $X$. Based on an equivalent characterization of sorted numbers, we derive an upper bound for $ξ_n$ and suggest a simple normalization aimed at reducing its bias for small sample size $n$. In Monte Carlo simulations of various models, the normalization reduced the bias in all cases. The mean squared error was reduced, too, for values of $ξ$ greater than about 0.4. Moreover, we observed that non-parametric confidence intervals for $ξ$ based on bootstrapping $ξ_n$ in the usual n-out-of-n way have a coverage probability close to zero. This is remedied by an m-out-of-n bootstrap without replacement in combination with our normalization method.
title A Simple Bias Reduction for Chatterjee's Correlation
topic Methodology
url https://arxiv.org/abs/2312.15496