ABSTRACT
This chapter introduces the concept, application, and computation of another set of descriptive measures that relate to an association between two or more variables. The measures that attempt to quantify such a relationship between the variables and further help to answer the strength of the relationship are called measures of association. The chapter examines two such measures, which are closely related to each other. These are covariance and correlation. The study of correlation is important as it quantifies the degree of association between the variables and shows how strongly the variables are related. Correlation can be categorized as follows: positive correlation, negative correlation, and zero correlation. The study of the correlation coefficient helps to determine the strength of the relationship between variables. The chapter focuses on Karl Pearson’s and Spearman’s methods to estimate the correlation coefficient. The Spearman correlation coefficient, unlike Pearson’s correlation coefficient method, is calculated for the data measured on ordinal or rank scale.
