how to display the maximum and minimum value of 5 data in an array

I created a php script to find the minimum and maximum values, but only 1 array data was detected, I want 5 maximal data and 5 minimum data, how it's work?

    <?php
                                               
$nilai = array("70", "75", "72", "71", "90", "55", "24", "74", "66", "30", "99", "100", "15", "47", "96"); //Array Nilai
echo "Nilai Siswa : "; //Tampilkan Tulisan Nilai Siswa
echo implode (", ", $nilai, ); //Tampilkan Data Array

$tinggi=max($nilai); //Nilai Maximal
$rendah=min($nilai); //Nilai Minimal

echo "<br>Daftar Nilai Terendah : $rendah";  // Tampilkan Nilai Minimal
echo "<br>Daftar Nilai Tertinggi: $tinggi <br>";  // Tampilkan Nilai Maximal
?>