# Student Resources

## Glossary

**Causation:** A statement describing a cause-effect relationship between two variables.

**Correlation:** A mutual relationship or connection between two variable quantities.

**Correlation Coefficient:** A value between −1 and +1 calculated to represent the linear dependence of two variables in a data set. The closer the value is to −1 or +1, the stronger the relationship. The correlation coefficient should only be used when a linear regression has been applied.

**Linear regression:** A technique in which a straight line is fitted to a set of data points to measure the effect of a single independent variable.

**Lurking variable:** An extraneous variable that may influence the interpretation of relationships among the given variables.

**Residual:** The difference between the actual, observed value and a value predicted by the regression equation.