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Statistics vocabulary · Descriptive Statistics

Interquartile range

Meaning in statistics, with examples

nounCommon term

In statistics, interquartile range means: The distance between the first and third quartiles (Q3 − Q1), showing how spread out the middle 50% of the data is.

In Turkish: çeyrekler açıklığı, çeyrekler arası açıklık

How it is used

Abbreviated IQR and reported with the median when data are skewed: 'median 6 days (IQR 4–11)'. Note that journals often give the two quartiles in brackets rather than their difference. Unlike the range, it is not affected by extreme values.

Example sentences

  1. Hospital stay had a median of 6 days and an interquartile range of 4 to 11 days.

  2. Because of the outliers, the interquartile range is a better measure of spread here than the standard deviation.

Common collocations

  • median and interquartile range
  • calculate the interquartile range
  • 1.5 times the IQR
  • report the IQR
  • quartileOne of the three values that divide ordered data into four equal parts: the first quartile (Q1), the median (Q2) and the third quartile (Q3).
  • medianThe middle value when the data are put in order from smallest to largest; with an even number of values, it is the mean of the two middle ones.
  • rangeThe difference between the largest and the smallest value in a data set; the simplest measure of spread.
  • box plotA chart that shows the median, the quartiles and the spread of the data as a box with lines (whiskers) extending from it, with outliers marked as separate points.
  • outlierAn observation that lies unusually far from most of the other values in a data set; it may come from an error or from a genuinely unusual case.

More terms: Descriptive Statistics

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