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Weighted modelfit

This chart is a variant of the standard ScatterPlot with the size of the markers used to show an extra dimension in the data. The third argument gives the required marker area (typically the number of incidents recorded at a certain location) and all the markers are automatically scaled to cover the range of areas given.

This example illustrates the way the regression line is weighted by the count at each data-point.

You can see that the fitted line is strongly biased towards the points with more data.

SharpPlot sp = new SharpPlot;

sp.Heading = "Weighted Regression";
ydata = new int[] {190,270,310,120,190,230};
xdata = new int[] {17,31,29,14,16,24};
count = new int[] {12,15,77,97,9,112};

sp.SetYTickMarks(50);

sp.SetMarkers(Marker.Lozenge);
sp.BubbleChartStyle = BubbleChartStyles.GridLines|BubbleChartStyles.ModelFit|
         BubbleChartStyles.HaloMarkers;

sp.DrawBubbleChart(ydata,xdata,count);
sp.SetKeyText(new string[]{"Incident count","Weighted model"});

Worked Examples

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