How to Calculate and Interpret Correlation Coefficients
TL;DR: When two variables move together on a scatterplot, how do you measure how tight that relationship really is? Enter r, the correlation coefficient. It runs from negative 1 (a perfect downward line) through 0 (no linear pattern at all) up to positive 1 (a perfect upward line). The sign tells you the direction; the […]
How to Know the Difference Between Correlation and Causation
TL;DR: Ice cream sales and shark attacks both spike in July, but ice cream doesn’t cause shark attacks. That’s the classic correlation-versus-causation trap in one example. Correlation just means two variables move together. Causation means one actually changes the other. A real correlation can come from a true cause, reverse causation, a lurking variable like […]