What is a correlation?

- Defined:	Correlation is the measure of the strength and direction of the relationship between the variables
- Variables:	IV is continuous, DV is continuous
- Relationship:	Relationship amongst variables
- Example	Relationship between height and weight.
- Assumptions:	Normality. Linearity.

What is a correlation?

Correlation is the measure of the strength and direction of the relationship between the variables
Direction of the relationship can be either positive or negative. Correlations can vary between -1 and 1. A positive relationship is indicated by a positive value (e.g., ranging from 0 to 1). A negative relationship is indicated by a negative value (e.g., ranging from 0 to -1). - An example of a positive relationship is the relationship between height and weight. The higher the outcome on one variable, the higher the outcome on the other variable. - An example of a negative relationship is the relationship between exercise and weight. The higher the outcome on one variable, the lower the outcome on the other variable.
Strength of the relationship is measured from 0 to 1/-1. The farther the value is away from 0, the stronger the relationship. The approximate criteria for strength is 0 for no effect, .1 for a small effect, .3 for a medium effect, and .5 for a large effect. Notice those values can be either positive or negative, depending upon the direction of the relationship, so a .2 and -.2 relationship indicate the same strength, but different direction