ACT Preparation / Unit 15 ACT 1411 short lesson, about 20 seconds
Range and Interquartile Range
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The idea
The range is the maximum minus the minimum; the IQR is the third quartile minus the first. Values more than 1.5 IQR past a quartile are potential outliers.
In practice
Quartiles of 20 and 32 give an IQR of 12, so values below 2 or above 50 are potential outliers.
Where people slip
The IQR resists outliers; the range does not.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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