And the correlation coefficient between the monthly rate of change for US stocks and oil (since 1973—as far back as I can get good monthly data for oil) is: -0.003. Which is a negative ...

The coefficient of determination shows the level of correlation between one dependent and one independent variable. It's also called r 2 or r-squared. The value should be between 0.0 and 1.0.

An Engel Curve is a graphic representation of Engel's Law, showing the relationship between household income and spending on a particular good or service. What Is Engel's Coefficient?