2.5 - 5-Number Summary

5-Number Summary
Minimum, \(Q_1\), Median, \(Q_3\), Maximum
\(Q_1\) is the first quartile, this is the 25th percentile
\(Q_3\) is the third quartile, this is the 75th percentile

Five number summaries are used to describe some of the key features of a distribution. Using the values in a five number summary we can also compute the range and interquartile range.


The difference between the maximum and minimum values.

\(Range = Maximum - Minimum\)

Note! The range is heavily influenced by outliers. For this reason, the interquartile range is often preferred because it is resistant to outliers.
Interquartile range (IQR)

The difference between the first and third quartiles.

\(IQR = Q_3 - Q_1\)