[Overview][Constants][Types][Classes][Procedures and functions] Reference for unit 'math' (#rtl)

popnvariance

Return population variance

Declaration

Source position: line 0

function popnvariance(

  const data: PFloat;

  const N: Integer

):float;

function popnvariance(

  const data: array [] of float

):float;

Description

Popnvariance 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

popnstddev

  

Return population variance

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. }

Uses math;

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

Var
  I : Integer;
  ExArray : TExArray;

begin
  Randomize;
  for I:=1 to 100 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.