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If this newsletter prompts you to ask your own questions about DOE, please address them via e-mail to: [email protected].
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PS. Quote for the month: A pearl of wisdom on dealing with error. (Page down to the end of this e-zine to enjoy the actual quote.) |
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Many of you have received, or soon will, a printed copy of the latest Stat-Teaser, but others, by choice or because you reside outside of North America, will get your only view of the May issue at this link. It features a report by me on results from an experiment done by a team of Auburn University students for their chemical engineering lab. See the results of their matchup of kidney versus lima beans subjected to varying conditions for germination. This is a good one to try at home with your budding scientists! Thank you for reading our newsletter. If you get the hard copy, but find it just as convenient to read what we post to the Internet, consider contacting us to be taken off our mailing list, thus conserving resources. (Note: You will be notified via the DOE FAQ Alert on new newsletter posts.) In any case, we appreciate you passing along hard copies and/or the link to the posting of the Stat-Teaser to your colleagues. *The capital letters pay homage to “Moneyball,” a book that touted the value of statistics for helping teams win at baseball. If Brad Pitt had played the part of the sabermetrician in the movie (not that nerdy-looking fellow), I’d have liked it better. ; )
Original Question: From a Quality Assurance Consultant: Answer: From Stat-Ease Consultant Wayne Adams:
In this case, the signal-to-noise ratio is one, so the relevant power is produced from default settings in Design-Expert—the middle column highlighted in the screen shot (a good result!). Resulting power calculation If you need to evaluate a different ratio, change the default via the Options provided prior to these Results under the Model setup screen. Contact Stat-Ease for further help on this if needed. We can be reached most readily via [email protected], or just give us a call and ask for assistance from a statistical consultant." (Learn more about power by attending the two-day computer-intensive workshop Experiment Design Made Easy. Click on the title for a description of this class and link from this page to the course outline and schedule. Then, if you like, enroll online.)
Original Question: From a Senior Mechanical Engineer: The results match with output from our general statistical software, a standard package used in industry for quality assurance purposes. However, now I am using Design-Expert to experiment on things such as plate thickness. How do I connect sample-size calculations like that shown above to what your software does with its power calculator for factorial designs?” Answer: From Stat-Ease Consultant Pat Whitcomb:
Response Surface Methods (RSM) can lead you to the peak of process performance. In this advance-level webinar encore presented on Wednesday, July 11 at 10:30 AM CDT*, Stat-Ease Consultant Pat Whitcomb will present an advanced-level webinar on robust design, propagation of error, and tolerance analysis. Propagation of error (POE) accounts for variation transmitted from deviations in factor levels. It finds the flats—high plateaus or broad valleys of response, whichever direction one wants to go—maximum or minimum; respectively. Tolerance analysis drills down to the variation of individual units, thus facilitating improvement of process capability. Stat-Ease webinars vary somewhat in length depending on the presenter and the particular session—mainly due to breaks for questions: Plan for 45 minutes to 1.5 hours, with 1 hour being the target median. When developing these one-hour educational sessions, our presenters often draw valuable material from Stat-Ease DOE workshops.
All of you who work in process industries (whether regulated or not), consider “Framing Your QbD Design Space with Tolerance Intervals to Verify Specifications” as I’ve detailed for the May print issue of PharmaQbD in the article posted here. The list of inspiring experiments at “Achieving Breakthroughs in Non-Manufacturing Processes via Design of Experiments (DOE)” now includes a great example from the US Bureau of Census showing how they improved their survey response via a factorial design. I heard about this from Professor Dan Rand of Winona State—a fellow speaker at the ASQ Hiawatha (MN) Section meeting earlier this year.) Comment: From Timothy M Michaelson, Senior Consultant, Manufacturing Excellence Group, International Paper:“I wrote my masters paper on fractional factorials so I can provide some interesting details regarding FAQ 1 on “Fold-over on resolution IV fractional two-level factorial did not de-alias interactions” in your DOE FAQ Alert, Volume 12, Number 2, Mar/Apr 2012. When you fold over an even resolution two-level fractional factorial, the resulting fraction remains the same even-resolution fraction (e.g., IV+IV=IV, VI+VI=VI). However, when you fold over an odd resolution two-level fractional factorial, the resulting fraction becomes a higher even-resolution fraction (e.g., III+III=IV, V+V=VI). Therefore, if you want to de-alias interactions by full fold-over, you need to start with an odd resolution fraction.”
You are invited to participate in our Fourth European Design of Experiments (DOE) User Meeting in Vienna, Austria. Find all the details here .
Consultant Brooks Henderson carries the Stat-Ease torch forward to the Quality by Design India 2012 conference (one of a series in this rapidly-developing nation) with our “Overview of DOE for QbD” workshop in Hyderabad on July 27. See the agenda here. |
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Seats are filling fast for the following DOE classes. If possible, enroll at least 4 weeks prior to the date so your place can be assured. However, do not hesitate to ask whether seats remain on classes that are fast approaching! Also, take advantage of a $395 discount when you take two complementary workshops that are offered on consecutive days. All classes listed below will be held at the Stat-Ease training center in Minneapolis unless otherwise noted.
* Take both EDME and RSM in February to earn $395 off the combined tuition!
** Take both MIX and MIX2 to earn $395 off the combined tuition!
Mark Mark J. Anderson, PE, CQE
For breaking news from Stat-Ease go to this Twitter site. DOE FAQ Alert ©2012 Stat-Ease, Inc. |
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