how do you figure the correlation coefficient?

Question

this s for a statistics class

Answer 1

The most common correlation (there are several) is described at:

http://mathworld.wolfram.com/CorrelationCoefficient.html

This is sometimes known as the "product moment correlation". Some others are: Spearman's rank order correlation and Kendall's tau.

Answer 2

http://en.wikipedia.org/wiki/Correlation_coefficient