Atualizar gráfico de distribuição normal usando JTextField no JFreeChart

Eu tenho uma classe que se estendeJPanel paraJFreeChart. Dentro desetMean(), Tentei atualizar valores dedataset ou apenas oFunction2D, mas nada muda no gráfico, mesmo comrepaint().

    public class JFreeChartPanel extends JPanel {
        Function2D normal = new NormalDistributionFunction2D(0.0, 3.0);
        XYDataset dataset = DatasetUtilities.sampleFunction2D(normal, -5.0, 5.0, 100, "Normal");

        double mean = 0.0, std = 1.0;

        public double getMean() {
            return mean;
        }

        public void setMean(double mean) {
            this.mean = mean;
            normal = new NormalDistributionFunction2D(mean,std);
            dataset = DatasetUtilities.sampleFunction2D(normal, -5.0, 5.0, 100, "Normal");
            repaint();
        }

        public double getStd() {
            return std;
        }

        public void setStd(double std) {
            this.std = std;
        }

        public JFreeChartPanel(){        

            JFreeChart chart = ChartFactory.createXYLineChart(
                "Normal Distribution",
                "X", 
                "Y", 
                dataset,
                PlotOrientation.VERTICAL,
                true,
                true,
                false
            );


            final ChartPanel chartPanel = new ChartPanel(chart);
            setLayout(new BorderLayout());
            add(chartPanel);
        }
}

E isso é executado toda vez que eu mudo o valor no meuJTextField.

public void updateMean()
    {
        String meanS = mean.getText();
        double mean = 0.0;
        try{
            mean = Double.parseDouble(meanS);
            System.out.println("Mean: "+mean);
            jFreeChartPanel.setMean(mean);
        }catch(Exception e){
            System.out.println("Mean: incorrect input");
        }
    }

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