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

# variance

Return variance of values

## Declaration

Source position: line 0

`function variance(`
`const data: array of Extended`
`):float; function variance(`
`const data: PExtended;`
`const N: Integer`
`):float;`

## Description

Variance returns the variance of the values in the data array. It returns zero if there is only one value.

The second form of the function accepts a pointer to an array of N values.

## Errors

None.

## See also

totalvariance |  | Return total varians of values
stddev |  | Return standard deviation of data
mean |  | Return mean value of array

## Example

    Program Example50;

    { Program to demonstrate the Variance function. }

    Uses math;

    Var
      I : 1..100;
      ExArray : Array[1..100] of Float;
      V : float;

    begin
      Randomize;
      for I:=low(ExArray) to high(ExArray) do
        ExArray[i]:=(Random-Random)*100;
      V:=Variance(ExArray);
      Writeln('Variance     : ',V:8:4);
      V:=Variance(@ExArray[1],100);
      Writeln('Variance (b) : ',V:8:4);
    end.

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