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

# PopnVariance

Return population variance

## Declaration

Source position: math.pp line 525

 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.

 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.
```