correlation coefficient

A number between -1 and +1 that expresses the strength of the linear association between two numerical variables.

Note: In a sample, the estimate is noted as r. A correlation coefficient of 0 indicates that there is no linear relationship between the two variables. A correlation coefficient of +1 indicates that there is a perfect positive linear relationship, and a correlation coefficient of -1 indicates that there is a perfect negative linear relationship.

Note: It cannot be concluded from the correlation that there is a cause-and-effect relationship.