What are Outliers?

Outliers are term used to describe specific numbers in a set of numbers that outweigh the rest of the set. An outlier can be a number that is way less or way more than the overall average of the rest of the number set. For example, in the number set 2, 3, 6, 7, 7, 9 and 21, the number 21 is the outlier because it stands out the most as being the greatest overall number.