MathPHP\Statistics\Average::cubicMean PHP Method

    public static function cubicMean(array $numbers)
    {
        $n = count($numbers);
        $∑xᵢ³ = array_sum(array_map(function ($x) {
            return $x ** 3;
        }, $numbers));
        return pow(1 / $n * $∑xᵢ³, 1 / 3);
    }