Phpml\Math\Statistic\Mean::mode PHP Method

    public static function mode(array $numbers)
    {
        self::checkArrayLength($numbers);
        $values = array_count_values($numbers);
        return array_search(max($values), $values);
    }

 public function testModeOnArray()
 {
     $numbers = [5, 2, 6, 1, 3, 4, 6, 6, 5];
     $this->assertEquals(6, Mean::mode($numbers));
 }