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    PopnVariance

    Return population variance.

    Declaration

    Source position: math.pp line 851

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

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

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

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

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

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

    Description

    Popnvariance the population variance of the values in the Data array. It returns zero if there is only one value.

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

    Errors

    None.

    See also

    Name Description
    popnstddev Return Population standard deviation.
    mean Return mean value of array.
    meanandstddev Return mean and standard deviation of array.
    stddev Return standard deviation of data.
    momentskewkurtosis Return 4 first moments of distribution.

    Example

    Program Example36;

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

Uses math;

Var
  I : Integer;
  ExArray : Array[1..100] of Float;

begin
  Randomize;
  for I:=low(ExArray) to high(ExArray) do
    ExArray[i]:=(Random-Random)*100;
  Writeln('Max           : ',MaxValue(ExArray):8:4);
  Writeln('Min           : ',MinValue(ExArray):8:4);
  Writeln('Pop. var.     : ',PopnVariance(ExArray):8:4);
  Writeln('Pop. var. (b) : ',PopnVariance(@ExArray[1],100):8:4);
end.