# Interquartile Range (IQR)

Interquartile range (IQR) is the middle half of a collection of numbers that are ordered from lowest to highest.

To find the interquartile range of a collection:

1. Find the median of the collection
2. Find the median of lower and upper half of the collection, leaving out the median number(s)
3. Subtract the lower half's median from the upper half's median. The difference is the $IQR$

## Broader Topics Related to Interquartile Range (IQR)

### Median

How to calculate the median of a collection of numbers

### Statistics

The analysis of numerical data