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Descriptive statistics summarize a data set. IQR (interquartile range) = Q3 − Q1 and is robust against outliers. Quartiles divide sorted data into four equal parts at Q1 (25%), Q2/median (50%), Q3 (75%).
Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.
What is the IQR used for?
The IQR measures the middle 50% spread of data. Outliers are often defined as points below Q1 − 1.5×IQR or above Q3 + 1.5×IQR (Tukey fences).
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