/**
* @test
*/
public function getStandarDeviation()
{
$values = $this->getValuesFromData($this->listFilteredByOneSubgroup(true));
$this->assertEquals(100, $this->statistic->sampleStandardDeviation($values));
$values->rewind();
$this->assertEquals(81.65000000000001, $this->statistic->populationStandardDeviation($values));
}
function testStandardDeviation(Statistic $statistic){
$values = new ArrayObject(array(3,5,2,1,3,4,6,9,3));
assertEquals($statistic->populationStandardDeviation($values->getIterator()), 2.26);
assertEquals($statistic->sampleStandardDeviation($values->getIterator()), 2.398);
}
