What is the 1.5 rule?
The 1.5 rule states that any data point more than 1.5 times the IQR below Q1 or above Q3 is considered an outlier.
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Analysis
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How to Use
Step-by-step instructions
- 1Enter your dataset separated by commas or spaces.
- 2The calculator will compute Q1, Q3, IQR, and identify potential outliers.
IQR Formula
The Interquartile Range (IQR) is the range of the middle 50% of the data. It is calculated as the difference between the third quartile (Q3) and the first quartile (Q1).
IQR = Q3 - Q1Variables:
Q125th PercentileQ375th PercentileExample
Dataset with Outlier
Inputs:
Data:1, 2, 3, 4, 5, 6, 7, 100
Steps:
- 1.Sorted: 1, 2, 3, 4, 5, 6, 7, 100
- 2.Q1 (Median of 1,2,3,4): 2.5
- 3.Q3 (Median of 5,6,7,100): 6.5
- 4.IQR: 6.5 - 2.5 = 4
- 5.Upper Fence: 6.5 + 1.5(4) = 12.5
- 6.Outliers: 100 (since 100 > 12.5)
Result:
IQR: 4, Outlier: 100