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PopnVariance

Return population variance

Declaration

Source position: math.pp line 533

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

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.