Distance correlation: Difference between revisions

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- updated intro to be more approachable for non-experts. larger focus on the ability to detect linear + nonlinear interactions, how dcorr can be used as a statistical test, and more scope for dcorr (i.e., kernel based methods, and its use in CCA and ICA)
Revise lede to be more understandable to non-experts.
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In [[statistics]] and in [[probability theory]], '''distance correlation''' or '''distance covariance''' is a measure of [[statistical dependence]] between two paired [[random vector]]s of arbitrary, not necessarily equal, [[Euclidean vector|dimension]]. InThe the limit of an infinite number of samples, thepopulation distance correlation coefficient is zero if and only if the random vectors are [[statistically independent]]. Thus, distance correlation can detectmeasures both linear and nonlinear interactionsassociation between two random variables or random vectors. This is in contrast to [[Pearson's correlation]], which can only detect linear interactionsassociation between two [[random variable]]s.
 
Distance correlation can be used to perform a [[Statistical hypothesis testing|statistical test]] of dependence with a [[permutation test]]. One first computes the distance correlation (involving the re-centering of Euclidean distance matrices) between two random vectors, and then compares this value to the distance correlations of many shuffles of the data.