An outlier is a value or data point that is far away from rest of the values or points of data.

Given the following marks (in percent) on an exam, the mark of 98 % could be considered to be an outlier as it is much higher than the rest of the marks (which are all greater than or equal to 52 % and less than or equal to 67 %).

A set of exam marks: { 52, 52, 55, 56, 56, 57, 58, 60, 60, 60, 60, 61, 61, 63, 64, 64, 64, 64, 64, 65, 66, 66, 66, 67, 98 }