MathPHP\Probability\Distribution\Continuous\Pareto::mean PHP Метод

    public static function mean($a, $b)
    {
        Support::checkLimits(self::LIMITS, ['a' => $a, 'b' => $b]);
        if ($a <= 1) {
            return INF;
        }
        return $a * $b / ($a - 1);
    }