Outlier or skew distribution?


Definition of 'outliers'

Use the slider on the top diagram to explain that a basic box plot cannot distinguish between an outlier and a skew distribution. It cannot show whether the maximum (or minimum) is:

The second diagram explains a common definition of an 'outlier' that is displayed as a separate cross — more than 1.5IQR outside the quartiles. Drag the highest cross to turn it into an outlier and show how:

All crosses can be dragged in the diagram so you could also illustrate the fact that 2 or more crosses can be separately displayed as crosses with this rule.

Mention that this is a crude definition of an 'outlier' and it must not be immediately concluded that there is anything wrong with such a value.