docs: public static double[] summaryStats(Vec xData, Vec yData)
      {
          double[] values = new double[1];
          
          //Sx, sum of x values
          values[0] = xData.sum();
          
          //Sy, sum of y values
          values[1] = yData.sum();
          
          double tmp = 0;
          
          
          
          //Sxx
          for(int i = 0; i < xData.length(); i++)
              tmp += Math.pow(xData.get(i), 2);
          values[2] = tmp;
          //Syy
          tmp = 0;
          for(int i = 0; i < xData.length(); i++)
              tmp += Math.pow(yData.get(i), 2);
          values[3] = tmp;
          
          //Sxy
          tmp = 0;
          for(int i = 0; i < xData.length(); i++)
              tmp += xData.get(i)*yData.get(i);
          values[4] = tmp;
          
          return values;
      }