It is a common observation that a data exploration should always begin by looking at a graphical display of the data. When looking at data sets which involve only one variable, displays such as bar charts and histograms are available. One problem with these is that they can include too much detail. Also they are not very useful for comparing two or more samples of data. A graphical display showing certain summary statistics in a visually appealing and interpretable way is introduced in this section. This is the boxplot.