CuSumStatus is a tabular or status CuSum chart. The tabular CuSum statistics are

 

 

By default, both statistics have initial value zero. The parameter K is the slack value (or allowance or reference value) and  is the expected mean.

The CuSumStatus chart contains two bar charts: a bar chart of  above the x-axis and a bar chart of  below the x-axis. There are also control limits at plus and minus H. The value of H can be set either as an absolute value or as a relative value h. They are related by, where   is the standard deviation. By default, bars which are out-of-control are filled red while in-control bars are green. The data is also plotted on the chart.

The CuSumStatus has a Print method to print the  and  values as well as  and , where  is the number of consecutive periods since  rose above zero.

CuSumStatus Example

This example uses the same data as used for the CuSum and EWMA examples. In this example .

(Download Code)

 

using Imsl.Chart2D;

using Imsl.Chart2D.QC;

using System.Drawing;

 

public class SampleCuSumStatus : FrameChart {

    static double[] data = {

        9.45, 7.99, 9.29, 11.66, 12.16, 10.18, 8.04, 11.46,

        9.20, 10.34, 9.03, 11.47, 10.51, 9.40, 10.08, 9.37,

        10.62, 10.31, 8.52, 10.84, 10.90, 9.33, 12.29, 11.50,

        10.60, 11.08, 10.38, 11.62, 11.31, 10.52

    };

 

    public SampleCuSumStatus() {

        double expectedMean = 10;

        double slackValue = 0.5;

 

        Chart chart = this.Chart;

        AxisXY axis = new AxisXY(chart);

        CuSumStatus cusumStatus =

            new CuSumStatus(axis, data, expectedMean, slackValue);

        cusumStatus.RelativeH = 4;

        cusumStatus.Print();

 

        axis.AxisX.AxisTitle.SetTitle("Sample Number");

        axis.AxisX.AxisLabel.TextFormat = "0";

        axis.AxisY.AxisTitle.SetTitle("C+ / C-");

 

        axis.AxisX.SetWindow(0, 30);

        axis.AxisX.AutoscaleInput = 0;

 

        cusumStatus.AddDataMarkers();

        cusumStatus.DataMarkers.MarkerSize = 0.5;

        cusumStatus.DataMarkers.MarkerColor = Color.Blue;

        cusumStatus.DataMarkersAxis.AxisY.AxisTitle.SetTitle(

            "Original Data");

 

        cusumStatus.BarPlus.GetBarSet(0,0).FillType =

            Data.FILL_TYPE_NONE;

        cusumStatus.BarMinus.GetBarSet(0,0).FillType =

            Data.FILL_TYPE_NONE;

        cusumStatus.BarPlus.GetBarSet(0,0).FillOutlineColor =

            Color.Green;

        cusumStatus.BarMinus.GetBarSet(0,0).FillOutlineColor =

            Color.Green;

    }

 

    public static void Main(string[] argv) {

        System.Windows.Forms.Application.Run(new SampleCuSumStatus());

    }

}

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