Strength of relationship

The most important information that a scatterplot shows is the strength of the relationship between the variables. The closer the points to a straight line or curve, the stronger the relationship.

If higher values of one variable tend to be associated with higher values of the other variable, the crosses on the scatterplot will be in a band with positive slope and the relationship is said to be positive. If high values of one variable tend to be associated with low values of the other variable, we say that there is a negative relationship.