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    TotalVariance

    Return total variance of values.

    Declaration

    Source position: math.pp line 844

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

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

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

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

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

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

    Description

    TotalVariance returns the total variance of the values in the data array. 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
    variance Return variance of values.
    stddev Return standard deviation of data.
    mean Return mean value of array.

    Example

    Program Example49;

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

Uses math;

Type
  TExArray = Array[1..100] of Float;

Var
  I : Integer;
  ExArray : TExArray;
  TV : float;

begin
  Randomize;
  for I:=1 to 100 do
    ExArray[i]:=(Random-Random)*100;
  TV:=TotalVariance(ExArray);
  Writeln('Total variance     : ',TV:8:4);
  TV:=TotalVariance(@ExArray[1],100);
  Writeln('Total Variance (b) : ',TV:8:4);
end.