title: How would I create a JFreeChart scatterplot best fit line
body: <p>I have an arraylist of points I want to include in a JFreeChart scatterplot. That works fine, but I now want a best fit line on it. After some searching, JFreeChart doesn't support such calculations directly, so what I want to do is calculate it myself and then stick a line into the chart manually. How do I get a line in a scatterplot?</p>
  
  <pre><code>        XYSeries series = new XYSeries("Data");
          for (Point p : points) {
             series.add(p.getX(), p.getY());
          }
          XYSeriesCollection dataset = new XYSeriesCollection(series);
          JFreeChart chart = ChartFactory.createScatterPlot(chartName, "Mass", parameter, dataset, PlotOrientation.VERTICAL, false, true, true);
          return chart;
  </code></pre>