private void btnStat_Click(object sender, EventArgs e)
 {
     if (chart1.Series.Count != 2)
     {
         _MessageService.ShowWarning(this, "Two series are required!");
     }
     else
     {
         var xx = (from pt in chart1.Series[0].Points select pt.YValues[0]).ToArray();
         var yy = (from pt in chart1.Series[1].Points select pt.YValues[0]).ToArray();
         if (xx.Length != yy.Length)
         {
             return;
         }
         lvStatistics.Items[0].SubItems[3].Text = MyStatisticsMath.Mse(xx, yy).ToString("F3");
         lvStatistics.Items[1].SubItems[3].Text = MyStatisticsMath.RMse(xx, yy).ToString("F3");
         lvStatistics.Items[2].SubItems[3].Text = MyStatisticsMath.Correlation(xx, yy).ToString("F3");
         lvStatistics.Items[3].SubItems[3].Text = MyStatisticsMath.NashStucliffeR(xx, yy).ToString("F3");
         // lvStatistics.Items[4].SubItems[3].Text = MyStatisticsMath.GetSimilarityScore(xx, yy).ToString("F3");
     }
 }