# Iterative Computation of Correlation Coefficient

Given a set of $k$ data points $A$, I have the correlation coefficient between them as $\rho_A$. Now I want to iterate over a new set of data points $B$ (say $j$ of them) and wish to iteratively compute the new value of correlation coefficient.

To be clear, I will select a point $x \in B$ , include it in the new set and delete an old point, say $y \in A$ to form a new set of points $A'$ = $A \cup$ {$x$} - {$y$}. Then, my query is there a straight forward formula to calculate the correlation coefficient $\rho_{A'}$ for $A'$ ?

Disclaimer : Not a homework problem but something I am looking in my research in data mining

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