PhpBench\Math\Statistics::stdev PHP Метод

    public static function stdev(array $values, $sample = false)
    {
        $variance = self::variance($values, $sample);
        return \sqrt($variance);
    }

 /**
  * It should return the standard deviation.
  */
 public function testStdev()
 {
     $this->assertEquals(1.4142, round(Statistics::stdev(array(1, 2, 3, 4, 5)), 4));
     $this->assertEquals(17.2116, round(Statistics::stdev(array(13, 23, 12, 44, 55)), 4));
     $this->assertEquals(0, round(Statistics::stdev(array(1)), 4));
     $this->assertEquals(0, round(Statistics::stdev(array(1, 1, 1)), 4));
     $this->assertEquals(2.47, round(Statistics::stdev(array(2, 6, 4, 1, 7, 3, 6, 1, 7, 1, 6, 5, 1, 1), true), 2));
 }