Plots and outliers

This activity (on the Australian Bureau of Statistics' website) is from CensusAtSchool and is called Box and Whisker Plots with Outliers of Money Earned.

Each student downloads two sets of randomly sampled data on the amount of money earned or received.

They draw two box plots and use the interquartile range formula to identify outliers.

An outlier in two variable data can also be identified by examining whether removing this data item from the set strengthens the association between the two variables.

The activity An Outstanding Cricketer: Student Worksheet illustrates why Sir Donald Bradman's performance would be considered an outlier when compared with other number three batsmen.

The short video Scatter Plots demonstrates how an Excel spreadsheet can be used to draw a range of scatterplots to identify the outlier in the cricket data. 

You can download the Scatter Plots video transcript.

The Beware of Outliers: Student Worksheet provides an activity based on outliers and the mean. You can also download the Beware of Outliers: Teacher Notes.