Statistics & probability
Interquartile outlier finder
List values outside configurable interquartile-range fences.
A clear answer. Here’s how.
Computes Q1 and Q3 by inclusive linear interpolation (type 7). Flags values strictly below Q1−multiplier×IQR or above Q3+multiplier×IQR, retaining input positions. A flag is a descriptive rule, not a reason to delete an observation. Zero IQR can flag every value different from the quartiles.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Values, separated by commas or new lines
- 2, 4, 4, 4, 5, 5, 7, 9
- IQR fence multiplier
- 1.5
Example result
| Input position | Value | Flag |
|---|---|---|
| 8 | 9 | Above upper fence |
Q1 4; Q3 5.5; IQR 1.5; fences 1.75 to 7.75. Type 7 quartiles.