VARIANCES (variance of a sample)

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VARIANCES(dataset [,meanofset])

 

 

VARIANCES

Returns the variance of a sample of a numeric set.

dataset

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

meanofset

A numeric constant or variable representing the average of the data set's values (optional).

 

VARIANCES computes the variance of a given sample data set. VARIANCEP computes the variance of a given population data set. The 'Sample' function call should be used only if the data set contains less than all of a population's values. Both functions operate on on the numeric set defined by all the entries in the first component of the designated QUEUE (dataset).

The optional parameter helps to optimize the function. If not provided, the value is computed internally by the function.

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:

 

StatSetXY  QUEUE,PRE()

X           REAL

          END

VarianceOfSet      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

VarianceOfSet = VARIANCES(StatSetX) !call VARIANCES