Hallar la mediana de un arrray de números

function median($numbers) {
    sort($numbers);
    $totalNumbers = count($numbers);
    $mid = floor($totalNumbers / 2);

    return ($totalNumbers % 2) === 0 ? ($numbers[$mid - 1] + $numbers[$mid]) / 2 : $numbers[$mid];
}

echo median([1, 3, 3, 6, 7, 8, 9]); // 6
echo "<br>";
echo median([1, 3, 6, 7, 3, 8, 9]); // 6 (da igual el orden)
echo "<br>";
echo median([1, 2, 3, 6, 7, 9]); // 4.5