Almost every day you can find in media commentary that XYZ is causing stocks to fall (or rise). Such definitive statements are common—but what’s almost always missing is statistical proof. And if you ...

Correlation coefficients range from -1 to +1, indicating the strength of relationships between variables. Investors use correlation coefficients for portfolio diversification to reduce risk.

You've probably noticed certain things that have a clear relationship with one another. For example, the amount of petrol your car uses increases along with the number of kilometres you drive. Or, if ...