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Date: | Tue, 21 Feb 2012 06:34:08 -0800 |
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Richard, you can still use the central limit theorem for averages from the data population and do your analysis on the means instead of the individual values.
I would be curious to know if/how that works out
Regards,
Amol Kane | Process Engineer
AsteelFlash Group - US East
941 Route 38, Owego NY 13827
Phone: (607) 687-7669 Extn 349 | Website: www.asteelflash.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
Sent: Friday, February 17, 2012 3:22 PM
To: [log in to unmask]
Subject: Re: [TN] Correlation Factors for ROSE Testing & Cpk
Thanks to all who responded to this string. Realized it could strike a chord.
To carry this a step further on a very related topic...
Any of you guys ever try to run a Cpk on ROSE data sets? Most of the times I've tried to over the years, the data sets have been non-normal, single tailed distributions, with highest counts near zero and then tailing off towards 10.06. (Similar to having only the right side half of a normal distribution curve). They have defied data transformation to a normal distribution, hence can't really run a proper capability analysis (data of course must be normal for a Cpk).
You could of course (at least within Minitab) try to run as a non-normal distribution and just report a PpK, however with such a high count near zero it's next to impossible to find a statistically supportable non-normal distribution.
I would appreciate any related experiences and/or thoughts on this topic.
Rich Kraszewski
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
Sent: Thursday, February 16, 2012 2:00 PM
To: [log in to unmask]
Subject: [TN] Correlation Factors for ROSE Testing
While I realize that IPC specifically and the industry in general, does not support the use of ROSE correlation factors for the various testers, I have a need to see the official document that at one time quoted these specifically allowed factors.
I took a cursory look though all 230 pages of IPC TR 583 and didn't see that table.
I seem to recall a military specification that had that table. Was it 454? 28809, 2000?
Does anyone recall?
Rich Kraszewski / PLEXUS
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