Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Statistical.php
public static function MEDIAN(...$args)
    {
        $returnValue = Functions::NAN();

        $mArgs = [];
        // Loop through arguments
        $aArgs = Functions::flattenArray($args);
        foreach ($aArgs as $arg) {
            // Is it a numeric value?
            if ((is_numeric($arg)) && (!is_string($arg))) {
                $mArgs[] = $arg;
            }
        }

        $mValueCount = count($mArgs);
        if ($mValueCount > 0) {
            sort($mArgs, SORT_NUMERIC);
            $mValueCount = $mValueCount / 2;
            if ($mValueCount == floor($mValueCount)) {
                $returnValue = ($mArgs[$mValueCount--] + $mArgs[$mValueCount]) / 2;
            } else {
                $mValueCount = floor($mValueCount);
                $returnValue = $mArgs[$mValueCount];
            }
        }

        return $returnValue;
    }
public static function MEDIAN(...$args)
    {
        $returnValue = Functions::NAN();

        $mArgs = [];
        // Loop through arguments
        $aArgs = Functions::flattenArray($args);
        foreach ($aArgs as $arg) {
            // Is it a numeric value?
            if ((is_numeric($arg)) && (!is_string($arg))) {
                $mArgs[] = $arg;
            }
        }

        $mValueCount = count($mArgs);
        if ($mValueCount > 0) {
            sort($mArgs, SORT_NUMERIC);
            $mValueCount = $mValueCount / 2;
            if ($mValueCount == floor($mValueCount)) {
                $returnValue = ($mArgs[$mValueCount--] + $mArgs[$mValueCount]) / 2;
            } else {
                $mValueCount = floor($mValueCount);
                $returnValue = $mArgs[$mValueCount];
            }
        }

        return $returnValue;
    }
MEDIAN.

Returns the median of the given numbers. The median is the number in the middle of a set of numbers.

Excel Function:
MEDIAN(value1[,value2[, ...]])

@category Statistical Functions

@param mixed ...$args Data values

@return float