Descriptive statistics are used to describe a study population. In this chapter it is shown that different statistics are used for continuous variables and for dichotomous or categorical variables. Furthermore, a distinction can be made between numerical descriptives and graphical descriptives. Numerical descriptives are, for example, the mean, median and measures to describe the spread in the data, such as the standard deviation. Graphical descriptives are, for example, a histogram and a stem-and-leaf plot.