ABSTRACT
Introduction Correlation is a quantitative estimate of the relationship between two or more variables. When we refer to simple correlation, we are measuring the strength and direction of the relationship beK tween a dependent variable (y) and one single independent variable (X). Although it is called simple correlation, this is not meant to suggest it is easy. Here, the word simple only refers to the case where there is one independent variable considered. This is in contrast to multiple correlaK tion. When we refer to multiple correlation, we are measuring the strength and direction of the relationship between a dependent variable (y) and more than one independent variables (Xn). This is a topic for Chapter 18.
