Glossary term
Outlier
A value that sits far away from most of the other values.
Visual intuition
30
31
32
33
most values
mean pulled right
300
One extreme value can drag summaries away from the cluster
One far-away value can pull the mean away from where most values sit.
Example
In 30, 31, 32, 33, and 300, the value 300 is an outlier.
How It Works
Outliers can be real signals, data errors, or rare cases. They matter because they can strongly affect summaries such as the , , and .
