IQR Calculator
Calculate the Interquartile Range (IQR) — the spread of the middle 50% of data.
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IQR
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Q1 (25th Percentile)
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Q3 (75th Percentile)
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Lower Fence
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Upper Fence
Recent Calculations
What Is IQR?
The Interquartile Range (IQR) is the range of the middle 50% of values. It's Q3 minus Q1 and is a robust measure of statistical dispersion.
Formula
IQR = Q3 − Q1Example
For {5, 7, 8, 12, 15}: Q1 = 6, Q3 = 13.5, IQR = 7.5.
Frequently Asked Questions
Why use IQR instead of range?
IQR isn't affected by outliers since it only looks at the middle 50% of data.
What are fences in statistics?
Lower fence = Q1 − 1.5×IQR, Upper fence = Q3 + 1.5×IQR. Data beyond these are potential outliers.