Process Capability

[Ca1icoJack]

Could someone please tell me how to calculate Cp, Cpk, Ppk, UCL(x), LCL(x), UCL(r) and LCL(r) in VBA?

Thank you very much

 

[SkipVought]

Hi,

Most spreadsheet functions can be called in VBA...

TheReturnValue = Application.[i]SpreadsheetFunction[/i](ArgumentValue1, ...ArgumentValuen)

Skip,
^{Don't let the Diatribe...
talk you to death!}
_{Just traded in my old subtlety...
for a NUANCE!}

 

[Ca1icoJack]

Okay... And if I were to use your method instead what formulae would I used in place of SpreadsheetFunction for each?

Thanks

 

[SkipVought]

Maybe I don't understand what "Cp, Cpk, Ppk, UCL(x), LCL(x), UCL(r) and LCL(r)" are. I have no idea in the world. Just thot that they might be spreadsheet function that you use from some AddIn.

Suppose you tell me.

Skip,
^{Don't let the Diatribe...
talk you to death!}
_{Just traded in my old subtlety...
for a NUANCE!}

 

[HughLerwill]

I recognize these as statistics for a Production Process; cp for instance is Process Capability and its formula is

cp = (SpecRange)/(6 * Standard deviation)

You will find formulas for the rest in any decent statistical text book or on Google.

You'll probably find that Excel will do a lot for you, as Skip has suggested, like the standard deviation calc etc.

 

[HughLerwill]

This one;

http://www.itl.nist.gov/div898/handbook/pmc/section1/pmc16.htm

looks promising and was close to the top for me in Google.