How to detect outliers in an ArrayList

How to detect outliers in an ArrayList

I'm trying to think of some code that will allow me to search through my
ArrayList and detect any values outside the common range of "good values."
Example: 100 105 102 13 104 22 101
How would I be able to write the code to detect that (in this case) 13 and
22 don't fall within the "good values" of around 100?