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**LOWERQUARTILE(****//dataset//****)**

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| 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  pth percentile value of a set .htm|PERCENTILE]], [[upperquartile  upper quartile value of a set .htm|UPPERQUARTILE]].

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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**