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Identifying outliers
In box plots, an outlier can be identified when using technology. This function may be turned on or off.
In the Australian Curriculum: Mathematics, an outlier is described as any data point that is more than 1.5 times the interquartile range (IQR, where IQR = Q3 – Q1) from either the upper quartile (Q3) or the lower quartile (Q1).


In the box plot above, any value less than 8.5 is an outlier.
Q1 – (1.5 \(\times\) IQR)= 13 – (1.5 \(\times\) 3) = 8.5
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.