Sunday, June 24, 2012

Plotting an OC Curve

I had been struggling with MS Excel to plot a damn OC Curve for about a week, until now. After spending considerable amount of time I realized that I should not choose a Line Chart but a Scatter Chart. I am not plotting a Scatter Chart but this is as close as you can get.

If anybody knows a better way, please let me know but the issue with selecting the Line Chart is that MS Excel draws two curves separately while the Scatter Charts correlate the two based on its definition and shows what we need. The only issues remaining is that the result is not a curve! It's a series of dots coming together and if you try to apply a Trend Line that really does not work because none of then have been actually are designed for this purpose. I guess the only software which could actually draw an OC Curve would be Minitab. I had an old copy from early 2000(!) which I used to use in the old country and brought it here. Have no idea where it is now. The newer versions must have the capability of drawing the Operating Characteristic Curve.
(Photos: The OC Curve and its related table plotted using MS Excel)

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