code: 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();
      }
docs: 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