Reference for package '#rtl'

PopnStdDev

Return Population standard deviation

Declaration

Source position: math.pp line 531

  function PopnStdDev(const data: Array of Single) : Float;
  function PopnStdDev(const data: PSingle; const N: Integer) : Float;
  function PopnStdDev(const data: Array of Double) : Float;
  function PopnStdDev(const data: PDouble; const N: Integer) : Float;
  function PopnStdDev(const data: Array of Extended) : Float;
  function PopnStdDev(const data: PExtended; const N: Integer) : Float;

Description

Popnstddev returns the square root of 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
popnvariance Return population variance
stddev Return standard deviation of data

Example

Program Example35;
{ Program to demonstrate the PopnStdDev function. }
{ @ should return typed pointer }
{$T+}
Uses Math;
Type
  TExArray = Array[1..100] of Float;
Var
  I : Integer;
  ExArray : TExArray;
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. stddev.     : ',PopnStdDev(ExArray):8:4);
  Writeln('Pop. stddev. (b) : ',PopnStdDev(@ExArray[1],100):8:4);
end.