Descriptive methodologies focus on analyzing historic data for the purpose of identifying patterns or trends. Analytic techniques that fall into this category are most often associated with exploratory data analysis which identifies central tendencies, variations, and distributional shapes. Descriptive methodologies can also search for underlying structures within data when no a priori knowledge about patterns and relationships are assumed. This can include correlation analysis, exploratory factor analysis, principal component analysis, trend analyses, and cluster analysis. The following tutorials walk you through common forms of descriptive analytics.