Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Statistical.php
public static function NORMDIST($value, $mean, $stdDev, $cumulative)
    {
        $value = Functions::flattenSingleValue($value);
        $mean = Functions::flattenSingleValue($mean);
        $stdDev = Functions::flattenSingleValue($stdDev);

        if ((is_numeric($value)) && (is_numeric($mean)) && (is_numeric($stdDev))) {
            if ($stdDev < 0) {
                return Functions::NAN();
            }
            if ((is_numeric($cumulative)) || (is_bool($cumulative))) {
                if ($cumulative) {
                    return 0.5 * (1 + Engineering::erfVal(($value - $mean) / ($stdDev * sqrt(2))));
                }

                return (1 / (self::SQRT2PI * $stdDev)) * exp(0 - (pow($value - $mean, 2) / (2 * ($stdDev * $stdDev))));
            }
        }

        return Functions::VALUE();
    }
public static function NORMDIST($value, $mean, $stdDev, $cumulative)
    {
        $value = Functions::flattenSingleValue($value);
        $mean = Functions::flattenSingleValue($mean);
        $stdDev = Functions::flattenSingleValue($stdDev);

        if ((is_numeric($value)) && (is_numeric($mean)) && (is_numeric($stdDev))) {
            if ($stdDev < 0) {
                return Functions::NAN();
            }
            if ((is_numeric($cumulative)) || (is_bool($cumulative))) {
                if ($cumulative) {
                    return 0.5 * (1 + Engineering::erfVal(($value - $mean) / ($stdDev * sqrt(2))));
                }

                return (1 / (self::SQRT2PI * $stdDev)) * exp(0 - (pow($value - $mean, 2) / (2 * ($stdDev * $stdDev))));
            }
        }

        return Functions::VALUE();
    }
NORMDIST.

Returns the normal distribution for the specified mean and standard deviation. This
function has a very wide range of applications in statistics, including hypothesis
testing.

@param float $value
@param float $mean Mean Value
@param float $stdDev Standard Deviation
@param bool $cumulative

@return float