Unit 'Math'	Package
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PopnVariance

Return population variance.

Declaration

Source position: math.pp line 744

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

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;
  or:=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.