'------------------------------------------------------------------ 
'   BCX Implementation of the Standard Deviation Function 
'------------------------------------------------------------------ 
SET A[] AS DOUBLE
  1, 5, 9, 3, 10, 4 ' Small Set Of Sample Data 
END SET

DIM Result AS DOUBLE ' The answer = 3.502380149323707 

Result = StDev(&A[0], 6) : PRINT "The Standard Deviation = ", Result#

FUNCTION StDev (Sample[] AS DOUBLE, Elements) AS DOUBLE
  DIM Total AS DOUBLE
  DIM Mean  AS DOUBLE
  DIM Srs   AS DOUBLE
  DIM Tmp   AS INTEGER
  FOR Tmp = 0 TO Elements - 1
    Total = Total + Sample[Tmp]
  NEXT
  Mean = Total / Elements
  FOR Tmp= 0 TO Elements - 1
    Srs = Srs + POW(ABS(Sample[Tmp] - Mean), 2)
  NEXT
  FUNCTION = SQRT(Srs / (Elements - 1))
END FUNCTION

Result:

The Standard Deviation =  3.50238014308365