## Correlation

a measure of the strength and direction of the association/relation between two variables.

Might be none (r≈0).

Correlation *might* mean one variable causes the other but by itself is insufficient to establish causation.

Pearson's product moment correlation coefficient r.

-1 ≤ *r* ≤ 1
Direction:

x,y both go up together and both go down together: positive *r*.

One goes up, the other goes down: negative *r*.

Strength: the closer *r* is to |1|, the stronger the relationship/association.