SDEVIATIONS (standard deviation of a sample)

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SDEVIATIONS(dataset [,meanofset])

SDEVIATIONS

Returns the standard deviation 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.

 

SDEVIATIONP computes the standard deviation of a given population data set. SDEVIATIONS computes the standard deviation of a given sample data set. The 'Sample' function call should be used only if the data set contains less than all of a population's values. The function operates 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

StandardDeviation    REAL

 

CODE                                  !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

 StandardDeviation = SDEVIATIONS(StatSetX)     !call SDEVIATIONS