Covariance is a measure of relationship (or co-movement) between two variables. Correlation is just the translation of covariance into a UNITLESS measure that we can...
Free learning from The Open University - www.open.edu --- Because two things happen, it doesn't mean they're related. Hans Rosling explains why correlation causes confusion....
A short tutorial on calculating a correlation matrix in SPSS (now known as PASW). Describes the range and strength of associations, as well as positive...