The displayed boxplot is based on the data shown on the left side of the screen. Notice that various aspects of the boxplot such as the mean and median are labeled. These labels can be hidden by unchecking the "show labels on boxplot" button.

Beneath the data is a pair of buttons that let you specify whether you want to be able to enter data or to see statistics based on the data. You can modify the data or delete it all (by pressing the "Clear All button") and enter your own data. Your data can be typed in or pasted in from another application. When pasting, you must use the keyboard shortcut for pasting (Command-V for Mac, CTRL-V for Windows. When you change the data, the boxplot will disappear. After you have entered new data, click the "Draw boxplot" button to redraw the boxplot.

Modify the data in various ways and see how it affects the boxplot. Try putting in some extreme values and see if they get labeled as outliers. Outside values are shown as "o's" beyond the inner fence. Far out values are shown as *'s outside the outer fence.