This document discusses different methods for correlating and comparing data sets. It describes four types of correlation - Pearson, point-biserial, Spearman rank-order, and chi-square test of independence - that determine how variables relate. The Pearson correlation is used for interval/ratio scales, point-biserial for dichotomous and continuous variables, Spearman for ranked data, and chi-square for categorical frequencies. Methods for comparing means include t-tests for independent and dependent samples to analyze two groups, and ANOVA to analyze three or more groups.