D

I generate an SPC data charts that are each comprised of thousands of data points. The SPC chart presents range, cp, cpk, max, min, min, std dev.

If I am trying to determine the overall process capability and calculate an UCL/LCL should I use all l of the data points (numbering in the millions of data points) and generate the the statistical data from all of that data. (this would be very labor intensive to get all the data into one spreadsheet).

Or

Do I use the max/min range from the SPC data?

or

Do I use the Mean +/- 3 std dev

or

do I perform a majic spell on the data....

Those are all the ideas that I have - hopefully I have supplied enough information on the data that I have and the question. If not please let me know.

Thanks for the help.

Dave