How to Calculate PPK in Excel?

I'm suppose to enter PPK formula into an Excel sheet, based on what I've found so far, I know PPK formula can be based on USL or LSL.

A- what should I do if I want to use one general formula regardless of USL or LSL value?

In this formula min((USL-mean/3*std.dev),(mean-LSL/3*std.dev)) 

B- what's the role of comma? What operation does it suggest?

C- Am I suppose to use this whole formula or each parenthesis is separate?    

2 Answers

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  • 1 month ago

    I think DEBS answered ALL your question

    1) the comma is part of the Excel Function 'MIN'  like this

    =MIN(FirstNumber,SecondNumber) 

    or even

    =MIN(#1,#2,#3,#4...)

    The comma separates numbers in an array for comparison.

    2) the parenthesis YOU have used to create additional formulas in the MIN function.  If you choose to NOT use the formulas you state in your question, then you don't have to use the Parentheses.  Debs shows how to do this using Cell references both with a Parenthesis and without. Again referring to the comma, the comma separates two (or more!) items of which you wish to find the MIN value.  

  • 1 month ago

    I can't comment on PPK specifically, but to your question about the MIN formula, the comma separates the two values you want compare.  So you are comparing USL-mean/3*std.dev to mean-LSL/3*std.dev and returning the lowest result into the cell it is in.

    Try it in a more simple form: min((A1-A2),B1-B2) or even min(1,400). The minimum value is always returned.

    • Thank you, that at least answers part of my question.

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