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    StdDev

    Return standard deviation of data.

    Declaration

    Source position: math.pp line 836

    function StdDev(const data: Array of Single) : Float;

    function StdDev(const data: PSingle; const N: Integer) : Float;

    function StdDev(const data: Array of Double) : Float;

    function StdDev(const data: PDouble; const N: Integer) : Float;

    function StdDev(const data: Array of Extended) : Float;

    function StdDev(const data: PExtended; const N: Integer) : Float;

    Description

    Stddev returns the standard deviation of the values in Data. It returns zero if there is only one value.

    The second form of the function accepts a pointer to an array of N values.

    Errors

    None.

    See also

    Name Description
    mean Return mean value of array.
    meanandstddev Return mean and standard deviation of array.
    variance Return variance of values.
    totalvariance Return total variance of values.

    Example

    Program Example40;

{ Program to demonstrate the stddev function. }
{ @ should return typed pointer }
{$T+}

Uses Math;

Var
  I : Integer;
  ExArray : Array[1..10000] of Float;

begin
  Randomize;
  for I:=low(ExArray) to high(ExArray) do
    ExArray[i]:=Randg(1,0.2);
  Writeln('StdDev     : ',StdDev(ExArray):8:4);
  Writeln('StdDev (b) : ',StdDev(@ExArray[1],10000):8:4);
end.