Question

How do you identify outliers when displaying data in a boxplot?

Answer 1

Outliers occur when outside the range of `Q1-1.5(IQR)` and `Q3+1.5(IQR)`, where `IQR` means Interquartile range, or the third quartile minus the first quartile. `Q1` is the first quartile and `Q3` is the third quartile.

If an outlier occurs, it is graphed on the box-and-whisker plot as a dot. For example, the outlier here is at the data value `95`:

Hope this helps!