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Process Capability Distribution Column Property & Control Charts

Hi all-- I have a column with a property to define the process capability distribution as lognormal. But when I run Control Chart, it still does all the capability analysis assuming a normal distribution. Is this a bug? Or is it intentional that Control Charts always assume a normal distribution, regardless of what the distribution is defined by in the column property?

Re: Process Capability Distribution Column Property & Control Charts

Makes sense, thanks.

Re: Process Capability Distribution Column Property & Control Charts

Xbar and R/S control charts are most similar to repeated Z or t tests and as such they assume a normal distribution.

There aren't any charts in JMP that work with the lognormal distribution (there are charts in JMP for situations where you have binomial, Poisson, negative binomial, and Weibull).

The easiest thing to do in this scenario (lognormal data) is to create a new formula column with the logged data, then feed that to the control chart...

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