Taken from the Lesson 4.2.1 Math Notes box:
An association (relationship) between two numerical variables can be described by its form,
direction, strength, and outliers.
The shape of the pattern is called the form of the association: linear or nonlinear.
The form can be made of clusters of data.
If one variable increases as the other variable increases, the direction is said to be a positive
association. If one variable increases as the other variable decreases, there is said to be a
negative association. If there is no apparent pattern in the scatterplot, then the variables
have no association.
A very strong positive non-linear association with no apparent outliers.