Normal correlation refers to the statistical relationship between two variables that have a normal distribution. However, there are several synonyms for this term, including linear correlation, Pearson correlation, and bivariate correlation. A linear correlation is a measure of the strength and direction of the relationship between two variables that can be represented by a straight line. The Pearson correlation coefficient is a measure of the strength and direction of a linear relationship between two variables. Finally, a bivariate correlation is a measurement of the strength and direction of association between two variables that have been measured at the same point in time. All of these terms refer to the statistical relationship between two variables and are used in different contexts depending on the research question being asked.