Linear and Nonlinear Association

• x > x mean and y > y mean then cov is positive

• x < x mean and y < y mean then cov is positive

• Otherwise is negative

R: -1 - 1

Quantifies the strength of the linear relationship

A correlation of zero does not necessarily mean that there is no relationship, but if there is no relationship, the correlation will be zero

Nonlinear

rho or p

built on mean and std

Spearman’s rank correlation captures how monotonic the relationship between two variables is

Has to be monotonic