MathPHP\Statistics\Average::lehmerMean PHP Method

    public static function lehmerMean(array $numbers, $p)
    {
        // Special cases for infinite p
        if ($p == -\INF) {
            return min($numbers);
        }
        if ($p == \INF) {
            return max($numbers);
        }
        // Standard case for non-infinite p
        $∑xᵢᵖ = array_sum(array_map(function ($x) use($p) {
            return $x ** $p;
        }, $numbers));
        $∑xᵢᵖ⁻¹ = array_sum(array_map(function ($x) use($p) {
            return $x ** ($p - 1);
        }, $numbers));
        return $∑xᵢᵖ / $∑xᵢᵖ⁻¹;
    }