/**
*
* @return null, \qtism\common\datatypes\Float
*/
protected function processPopVariance()
{
$operands = $this->getOperands();
$operand = $operands[0];
$result = OperatorsUtils::variance(self::filterValues($operand->getArrayCopy()), false);
return $result !== false ? new QtiFloat(floatval($result)) : null;
}
/**
* @dataProvider varianceProvider
*
* @param array $sample
* @param boolean Apply Bessel's correction?
* @param number $expected
*/
public function testVariance(array $sample, $correction, $expected)
{
$result = OperatorsUtils::variance($sample, $correction);
$this->assertSame($expected, $result);
}
