CpK analysis

Question

what's the Cpk difference for below two ways calculation (for non-normal distribution data)?

1) using Distribution, continuous fit/smooth curve, non parametric density/specific limit, capability analysis

2) using Quality and Process/control chart/IR, capability analysis

thanks.

Mark_Bailey · Answer

You might have already realized that there is more than one method because there are different opinions about how capability and performance should be calculated and interpreted. Does your organization have a standard? If so, then I can help you pick the appropriate method in JMP. If not, then I would use the default method in JMP.

We have recently been harmonizing the calculations that appear in different platforms so that they are the same. Which version of JMP are you using?

Finally, is your process data normally distributed? If not, which distribution model do you use?

Vanessa8 · Answer

Thanks, but could you please help to suggest which method is normal for product Cpk calculation? through distribution platform or process control chart? thanks.

and the differences for these two methods

Mark_Bailey · Answer

Perhaps this recent discussion will help you.