docs: public static double Kurtosis(int[] values, double mean, double stdDeviation){
          double n = 0;
          for (int i = 0; i < values.length; i++)
              n += values[i];
          
          double part1 = n * (n + 1);
          part1 /= ((n - 1) * (n - 2) * (n - 3));
          
          double part2 = 0;
          for (int i = 0; i < values.length; i++) {
              part2 += Math.pow((i - mean) / stdDeviation, 4) * values[i];
          }
          
          double part3 = 3 * Math.pow((n - 1), 2);
          part3 /= (n - 2) * (n - 3);
          
          return part1 * part2 - part3;
      }