Calculate median and average in PHP

function calculate_median($arr) {
    $count = count($arr); //total numbers in array
    $middleval = floor(($count-1)/2); // find the middle value, or the lowest middle value
    if($count % 2) { // odd number, middle is the median
        $median = $arr[$middleval];
    } else { // even number, calculate avg of 2 medians
        $low = $arr[$middleval];
        $high = $arr[$middleval+1];
        $median = (($low+$high)/2);
    }
    return $median;
}

function calculate_average($arr) {
    $count = count($arr); //total numbers in array
    foreach ($arr as $value) {
        $total = $total + $value; // total value of array numbers
    }
    $average = ($total/$count); // get average value
    return $average;
}

As BramVanroy and other mentioned, array needs to be sorted. In my case I used sort($arr);.

Rewritten from javascript https://stackoverflow.com/a/45309555/2298745

Median PHP:

function median($values) {
  $count = count($values);
  if ($count === 0)  return null;
  asort($values);
  $half = floor($count / 2);
  if ($count % 2) return $values[$half];
  return ($values[$half - 1] + $values[$half]) / 2.0;
}