Interquartile Range Calculator — Formule
## How to Calculate the Interquartile Range
### Formula
**IQR = Q3 - Q1**
Q1 is the value below which 25% of observations fall, and Q3 is the value below which 75% fall. The IQR captures the spread of the middle 50% of the data, ignoring extreme tails.
### Outlier Fences
Values below Q1 - 1.5*IQR or above Q3 + 1.5*IQR are considered potential outliers by the Tukey fence rule.
### Formula
**IQR = Q3 - Q1**
Q1 is the value below which 25% of observations fall, and Q3 is the value below which 75% fall. The IQR captures the spread of the middle 50% of the data, ignoring extreme tails.
### Outlier Fences
Values below Q1 - 1.5*IQR or above Q3 + 1.5*IQR are considered potential outliers by the Tukey fence rule.
Exemple Résolu
A dataset has Q1 = 25 and Q3 = 75. Find the IQR and outlier fences.
- IQR = 75 - 25 = 50
- Lower Fence = 25 - 1.5 * 50 = 25 - 75 = -50
- Upper Fence = 75 + 1.5 * 50 = 75 + 75 = 150
- Any value below -50 or above 150 is a potential outlier