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#1
October 15th, 2003, 04:43 PM
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Data Analysis P-Charts
How do you create p-charts using upper control limits
(UCL) and lower contril limits (LCL) using the standard deviation..? 
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#2
October 15th, 2003, 05:35 PM
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Data Analysis P-Charts
A p-chart is just a line chart. You can indicate the control limits
with added lines, per the examples he http://www.geocities.com/jonpeltier/...s.html#AddLine I would use the point-and-error-bar method, with the point to the right of the chart, and use a "Show Values" data label on the points. I also have a poorly documented Dynamic Control Chart on my site that you might be able to hack to meet your needs: http://www.geocities.com/jonpeltier/...s.html#CtrlCht - Jon ------- Jon Peltier, Microsoft Excel MVP http://www.geocities.com/jonpeltier/Excel/index.html _______ wrote: How do you create p-charts using upper control limits (UCL) and lower contril limits (LCL) using the standard deviation..?
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#3
October 15th, 2003, 10:07 PM
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Data Analysis P-Charts
A p-chart is a line chart plotting a percentage. Usually this is a
percentage defective. For example, you inspect 250 patient records and you find 32 of them contain errors. In this case your number inspected is 250, your number defective is 32, and you would plot (on your line chart) the percentage or 12.8%. You do this for several "rows" or records. Next, you compute control limits like this: Upper limit = pbar + 3 * SQRT(pbar(1-pbar)/nbar) Lower limit = pbar - 3 * SQRT(pbar(1-pbar)/nbar) pbar = the average of ALL your percentages nbar= the avarage of ALL your number inspected values Your line chart will then contain 4 lines: Upper limit the percentage line plot Lower limit pbar If your number inspected changes drastically across all your records, you should consider computing limits FOR each record - in this case the upper and lower limits will not be straight lines. Good luck http://www.qualityadvisor.com "Jon Peltier" wrote in message ... A p-chart is just a line chart. You can indicate the control limits with added lines, per the examples he http://www.geocities.com/jonpeltier/...s.html#AddLine I would use the point-and-error-bar method, with the point to the right of the chart, and use a "Show Values" data label on the points. I also have a poorly documented Dynamic Control Chart on my site that you might be able to hack to meet your needs: http://www.geocities.com/jonpeltier/...s.html#CtrlCht - Jon ------- Jon Peltier, Microsoft Excel MVP http://www.geocities.com/jonpeltier/Excel/index.html _______ wrote: How do you create p-charts using upper control limits (UCL) and lower contril limits (LCL) using the standard deviation..?
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