code: public static function STANDARDIZE($value, $mean, $stdDev)
      {
          $value = Functions::flattenSingleValue($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();
              }
  
              return ($value - $mean) / $stdDev;
          }
  
          return Functions::VALUE();
      }
docs: STANDARDIZE.
  
  Returns a normalized value from a distribution characterized by mean and standard_dev.
  
  @param float $value Value to normalize
  @param float $mean Mean Value
  @param float $stdDev Standard Deviation
  
  @return float Standardized value