public static function mean(int $ν, $μ)
{
Support::checkLimits(self::LIMITS, ['ν' => $ν, 'μ' => $μ]);
if ($ν == 1) {
return \NAN;
}
return $μ * sqrt($ν / 2) * Special::gamma(($ν - 1) / 2) / Special::gamma($ν / 2);
}