Pearson's correlation coefficient

Pearson's correlation coefficient is calculated as follows:

$r={\frac {\sum xy-\sum x\sum y}{\sqrt {(n\sum x^{2}-(\sum x)^{2})(n\sum y^{2}-(\sum y)^{2})}}}$

Part of M7-Quantitative Decision Methods-S7 - Correlation and Time series See also: http://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient