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1: Newsletter Alert:
The December issue of the Stat-Teaser details a DOE on how to keep the heat in a cup of tea—‘tis the season for warm beverages!
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 September issue at this link. It features a DOE that tested a claim by an insulated-mug maker that they “Keep Hot Drinks Hotter & Cold Drinks Colder Longer.”
This Stat-Teaser also provides a heads-up by me on “What is Mixture Design and What's In It for You?”
Thank you for reading our Stat-Teaser 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.
2: FAQ: How to handle constraints on a mixture experiment via optimal design
Original Question:
From a Chemical engineer:
"I recently came across an informative detailing of “Mixture and mixture process variable experiments for pharmaceutical applications” by Christine Anderson-Cook, Heidi Goldfarb, Connie Borror, Douglas Montgomery, et al in Pharmaceutical Statistics (Oct/Dec 2004, Vol. 3, Issue 4, pp 247-260). Therein, an example of the use of Design-Expert software is given,
where the mixture investigated is of three excipients that must make up 75% of a formulation (the active is fixed at 25%). I am trying to use Design-Expert the same way, but I am unable to include the said constraint (using the simplex centroid design). I am not sure I can see the option for a D-optimal design (referred to by the authors)."
Answer:
From Stat-Ease Consultant Shari Kraber:
"A simplex centroid (or lattice) design can only be used when all components have the same range. So when we have constraints (the majority of the cases), an optimal design must be used. If you have updated to version 8 of Design-Expert,* then the option on the Mixture tab is simply called “Optimal” now, because we have expanded the types of optimal designs available. The new default for response surface and mixture designs is I-V optimal, but D is still an option on the drop-down list for “Optimality."
(Learn more about component constraints by attending the two-day computer-intensive workshop "Mixture Design for Optimal Formulations." Click on the title for a
complete description and link from this page to the course outline
and schedule. Then, if you like, enroll online.)
*Version 8.0.4 of Design-Expert(R) software is posted here for free trial evaluation. This web site also provides free patches to update older licensed versions of 8.0. If you haven't upgraded to v8 yet, click here to learn what you're missing. Version 8 offers many useful features for design (such as I-V optimality) and analysis, as well as nicer-looking and more functional graphics. Why short yourself?
3: Webinar alert: DOE Made Easy and More Powerful via
Design-Expert Software, Part Three—Multicomponent Mixture Design for Optimal
Formulation
Keeping it simple and making it fun, Stat-Ease is introducing an
array of statistical methods for design of experiments (DOE) made
easy and more powerful via version 8 of Design-Expert software:
—Two-level factorials for process screening, characterization
and verification
—Response surface methods (RSM) for process optimization
—Multicomponent mixture design for optimal formulation.
I will present an encore of the third of this series of free webinars by
working through case studies on mixture experiments on Wednesday,
January 27th at 10:30 AM USA Central Time* (CT). 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. Attendance may be limited, so sign up soon by
contacting our Communications Specialist, Karen Dulski, via
[email protected]. If you can be accommodated, she will
provide immediate confirmation and, in timely fashion, the link
with instructions for our new web-conferencing vendor: GotoWebinar.
*(To determine the time in your zone of the world, try using this
link. We are
based in Minneapolis, which appears on the city list that you must
manipulate to calculate the time correctly. Evidently,
correlating the clock on international communications is even more
complicated than statistics! Good luck!)
4: Workshop Alert: See when and where to learn about DOE
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 up to 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.
See this link to a listing of upcoming classes for complete schedule and site information on all Stat-Ease
workshops open to the public. To enroll, click the "register online" link on our web site or call Elicia at 612.746.2038. If spots remain available, bring
along several colleagues and take advantage of quantity discounts in tuition. Or, consider bringing in an expert from Stat-Ease to teach a private class at
your site.****
**** Once you achieve a critical mass of about 6 students, it becomes very economical to sponsor a private workshop, which is most convenient and effective
for your staff. For a quote, e-mail [email protected].
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Please do not send me requests to subscribe or unsubscribe—follow the instructions at the very end of this message.
I hope you learned something from this issue. Address your general questions and comments to me at: [email protected].
Sincerely,
Mark
Mark J. Anderson, PE, CQE
Principal, Stat-Ease, Inc.
PS. Quote for the month—Counting our blessings:
"
The hardest arithmetic to master is that which enables us to count our blessings.”
—Eric Hoffer
Season’s greetings! MJA
Trademarks: Stat-Ease, Design-Ease, Design-Expert and
Statistics Made Easy are registered trademarks of
Stat-Ease, Inc.
Acknowledgements to contributors:
—Students of Stat-Ease training and users of Stat-Ease software
—Stat-Ease consultants Pat Whitcomb, Shari Kraber, Wayne Adams
and Brooks Henderson
—Statistical advisor to Stat-Ease: Dr. Gary Oehlert
—Stat-Ease programmers led by Neal Vaughn and Tryg Helseth
—Heidi Hansel Wolfe, Stat-Ease marketing director, Karen Dulski,
and all the remaining staff that provide such supreme support!
DOE FAQ Alert ©2010 Stat-Ease, Inc.
All rights reserved
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