Applied statistics can be divided into two areas: **descriptive statistics** and **inferential statistics**. Descriptive statistics consists of methods for organizing, displaying, and describing data by using tables, graphs, and summary measures. In contrast inferential statistics consists of methods that use sample results to make decisions or predictions about a population (Mann 2012, Weiss 2010).

The word univariate refers to the fact that only one variable is under consideration. The main purpose of univariate statistics is to describe and summarize the data. If two or more variables are analyzed, then we refer to bivariate or multivariate analysis or statistics, respectively. In this case we are primarily interested in the relationships between and among a set of variables.