Correlation is a synonym for association. Within the framework of statistics, the term correlation refers to a group of indices that are employed to describe the magnitude and nature of a relationship between two or more variables. As a measure of correlation, which is commonly referred to as a correlation coefficient, is descriptive in nature, it cannot be employed to draw conclusions with regard to a cause–effect relationship between the variables in question. To infer cause and effect, it is necessary to conduct a controlled experiment involving an experimenter-manipulated independent variable in which subjects are randomly assigned to experimental conditions. Typically, data for which a correlation coefficient is computed are also evaluated with regression analysis. The latter is a methodology for deriving an equation that ...