ABSTRACT
In several of the previous chapters, we examined statistics and parameters that describe a single variable at a time, such as the mean, standard deviation, z scores, and standard errors. Although such single-variable statistics are important, researchers are often interested in examining the relations among two or more variables. One of the most basic measures of the association among variables, and a foundational statistic for several more complex statistics, is the correlation coefficient. Although there are a number of different types of correlation coefficients, the most commonly used in social science research is the Pearson product-moment correlation coefficient. Most of this chapter is devoted to understanding this statistic, with a brief description of three other types of correlations: the point-biserial coefficient, the Spearman rho coefficient, and the phi coefficient.
