An Outlier is any data point/value that is significantly higher or lower than the other data points.
For example, Given the data below;
![3,4,3,5,4,3,29,4,5](https://img.qammunity.org/2023/formulas/mathematics/college/89fyivyh95luenpinp93m8ml9utbn1j6b6.png)
from the above data, the only data point/value that differs significantly from the other values is 29.
So, 29 is an outlier.