Outlier Detection Calculator — 公式
## How to Detect Outliers Using the IQR Method
### Formula
**IQR = Q3 - Q1**
**Lower Fence = Q1 - 1.5 * IQR**
**Upper Fence = Q3 + 1.5 * IQR**
Values below the lower fence or above the upper fence are flagged as potential outliers. The 1.5 multiplier is Tukey's convention. Using 3.0 instead identifies extreme outliers.
### Formula
**IQR = Q3 - Q1**
**Lower Fence = Q1 - 1.5 * IQR**
**Upper Fence = Q3 + 1.5 * IQR**
Values below the lower fence or above the upper fence are flagged as potential outliers. The 1.5 multiplier is Tukey's convention. Using 3.0 instead identifies extreme outliers.
计算示例
Q1 = 30, Q3 = 70. Is 95 an outlier?
- IQR = 70 - 30 = 40
- Lower fence = 30 - 1.5*40 = 30 - 60 = -30
- Upper fence = 70 + 1.5*40 = 70 + 60 = 130
- 95 is between -30 and 130, so it is NOT an outlier
- It would need to exceed 130 to be flagged