LOWERQUARTILE (lower quartile value of a set)

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LOWERQUARTILE(dataset)

 

 

LOWERQUARTILE

Returns the median of the lower half of an ordered numeric data set.

Dataset

The label of a QUEUE with its first component field defined as a REAL.

LOWERQUARTILE computes a value such that at most 25% of a numeric set's values are less than the computed value, and at most 75% of the set's values are greater than the computed value. The function operates on the numeric set defined by all the entries in the first component of the designated QUEUE (dataset). For example, given the data set: [1,2,3,4,5,6,7,8] the lower quartile value is 2.5.

In general, the LOWERQUARTILE function is only meaningful when the number of elements in the data set is large (ie. greater than 20).

See also:

PERCENTILE, UPPERQUARTILE.

 

The passed data set does not have to be sorted. The function copies the passed set. The passed data set is unchanged.

Return DataType:     REAL

 

Example:

 

StatSetX  QUEUE,PRE()

X          REAL

         END

 

LowerQuartileOfSet  REAL

 

CODE

FREE(StatSetX)                   !free the QUEUE

CLEAR(STADAT:RECORD)             !clear the record buffer

STADAT:Id = STA:Id               !prime the record buffer

STADAT:ItemNumber = 1

SET(STADAT:KeyIdItemNumber,STADAT:KeyIdItemNumber !position file pointer

LOOP                             !load the QUEUE

  NEXT(StatisticsData)           !read next record

  IF ERRORCODE() OR STADAT:Id NOT = STA:Id

    BREAK

  ELSE

    StatSetX:X = STADAT:X        !load the QUEUE buffer

    ADD(StatSetX)                !add to the QUEUE

  END

END

LowerQuartileOfSet = LOWERQUARTILE(StatSetX)   !call LOWERQUARTILE