In considering measures of centre, particularly the mean, it is important to be aware of the influence of outliers.
The Beware of Outliers: Student Worksheet and accompanying Beware of Outliers: Teacher Notes are based on a data set with an outlier.
The data are provided on the student worksheet.
The activity asks students to plot the data set with and without the outlier, and to observe the change in the mean.
Scale is considered in comparing graphs, as is the lack of change in the median, with and without the outlier.
