Quartiles

Quartiles[list]

gives a list of the 1/4, 1/2 and 3/4 quantiles of the elements in list.

Quartiles[dist]

gives a list of the 1/4, 1/2 and 3/4 quantiles of the distribution dist.

Details

  • Quartiles[list] is equivalent to Quantile[list,{1/4,1/2,3/4},{{1/2,0},{0,1}}]. »
  • The second quartile is equivalent to Median[list]. »
  • For even Length[list], the first quartile is equivalent to the median of the smallest elements in list.
  • For odd Length[list], the first quartile is equivalent to the average of the median of the smallest elements and the median of the smallest elements in list.
  • The third quartile is defined like the first, but with the largest rather than smallest elements.
  • Quartiles[list,{{a,b},{c,d}}] uses the quantile definition specified by parameters a, b, c, d.

Examples

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Basic Examples  (2)

Quartiles for a list of exact numbers:

Quartiles of a parametric distribution:

Scope  (14)

Data  (11)

Exact input yields exact output:

Approximate input yields approximate output:

Quartiles for a matrix gives columnwise quartiles:

Works with large arrays:

SparseArray data can be used just like dense arrays:

Compute results using other parametrizations:

Find the quartiles of WeightedData:

Find the quartiles of EventData:

Find the quartiles of TemporalData:

Find the quartiles of TimeSeries:

The quartiles depend only on the values:

Find the quartiles for data involving quantities:

Distributions and Processes  (3)

Find the quartiles for a parametric distribution:

Quartiles for a derived distribution:

Data distribution:

Quartile function for a random process:

Applications  (4)

Quartiles divide a distribution in four equal probability sections:

Find a moving quartile envelope for a time series:

Data smoothed by moving median:

Moving envelope of first and third quartiles:

Find the quartiles for data representing the top oil-producing fields in 2001:

Compare with the minimum and maximum values for the data:

Plot the data with quartile lines:

Compute the quartiles for the heights of children in a class:

Properties & Relations  (6)

Quartiles are given by linearly interpolated Quantile values:

The second quartile is the Median:

InterquartileRange is the difference between the first and third quartiles:

QuartileDeviation is half the difference between the first and third quartiles:

QuartileSkewness is a skewness measure obtained from the quartiles:

BoxWhiskerChart shows the quartiles for data:

Possible Issues  (1)

Quartiles requires numeric values:

Introduced in 2007
 (6.0)
 |
Updated in 2017
 (11.1)