1

Correlations: Relationship, Strength, & Direction

• Scatterplots are used to plot correlational data– It displays the extent that two variables are

related to one another

2

Relationship Strength

• The strength of a relationship between two variables is on a scale from -1 to 1– Stronger relationships are closer to -1 or 1– Weaker relationships are closer to 0

3

Examples of Scatterplots

4

Linear and Nonlinear Relationships

• Linear relationships are best described by a straight line

5

Nonlinear Relationships

• Nonlinear relationships are best described by another type of curve

6

Outliers

• Outliers are scores that are very different from the rest of the data

• They can dramatically impact the relationship between two variables