Issue: Volume 10, Number 9 (Circulation: Over 5500 worldwide)
Date: September 2010
From: Mark J. Anderson, Stat-Ease, Inc., Statistics Made Easy® Blog

Dear Experimenter,

Here's another set of frequently asked questions (FAQs) about doing design of experiments (DOE), plus alerts to timely information and free software updates. If you missed the previous DOE FAQ Alert, see below.

==> Tip: Get immediate answers to questions about DOE via the Search feature on the main menu of the Stat-Ease® web site. This not only pores over previous alerts, but also the wealth of technical publications posted throughout the site.

Feel free to forward this newsletter to your colleagues. They can subscribe by going to If this newsletter prompts you to ask your own questions about DOE, please address them via mail to:

Also, Stat-Ease offers an interactive web site — the Support Forum for Experiment Design at Anyone (after gaining approval for registration) can post questions and answers to the Forum, which is open for all to see (with moderation). Furthermore, the Forum provides program help for Design-Ease® and Design-Expert® software. Check it out and search for answers. If you come up empty, do not be shy: Ask your question! Also, this being a forum, we encourage you to weigh in!

For an assortment of appetizers to get this Alert off to a good start, follow this link,* and see a number of new blogs (listed below, beginning with the most recent one):

—Quantifying statements of confidence: Is anything 'iron clad'?
—Blah, blah, blah "quadratic"
—Opportunistic eating a problem for new college students

* Need a feed or e-mail updates from StatsMadeEasy? Go to It's easy! Even simpler: Just enter your e-mail in the new forwarding field and get new StatsMadeEasy blogs delivered directly.

"Your StatsMadeEasy blogs brighten up a dreary workday!"
—Applied Statistician, Florida

Topics in the body text of this DOE FAQ Alert are headlined below (the "Expert" ones, if any, delve into statistical details).

1. Newsletter Alert: August issue of the Stat-Teaser gives DOE a second whirl around for making popcorn —augmenting the original design to a response surface method (RSM) via an optimal algorithm
2. FAQ: When should one consider augmenting to an RSM design?
3. Webinar Alert: 2nd Encore of DOE Made Easy and More Powerful via Design-Expert Software, Part 2—Response Surface Methods (RSM) for Process Optimization (at a time convenient for Europe)
4. Events alert: Practical aspects of algorithmic design of physical experiments from an engineer’s perspective
5. Workshop alert: See when and where to learn about DOE

P.S. Quote for the month: An amusing example of being un-clear on cause-and-effect relationships.

(Page down to the end of this e-zine to enjoy the actual quote.)


1. Newsletter Alert: August issue of the Stat-Teaser gives DOE a second whirl around for making popcorn—augmenting the original design to a response surface method (RSM) via an optimal algorithm

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 August issue at It features a second "Whirley Pop DOE" by Consultant Brooks Henderson who shows his 'chops' by an optimal design augmentation using version 8 of Design-Expert® software (DX8).

This Stat-Teaser also provides a detailing by Consultant Shari Kraber of the new DX8 capability for displaying confidence, prediction, or tolerance intervals on the multiple-response 'overlay plot' provided with graphical optimization. This feature makes Design-Expert ideal for the FDA’s QbD (quality by design) initiatives.

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: When should one consider augmenting to an RSM design?

-----Original Question-----
Research Scientist
"How do I explain in plain English for my technical colleague why, with your expert guidance, we chose to augment our two-level factorial to an RSM design?"

Answer (from Stat-Ease Consultant Wayne Adams):
"Simply put a factorial design’s purpose is to discover important singular (main) and interaction effects. Center points can be added to numeric factors to test for curvature. If curvature is significant and you are interested in modeling the current experimental region, then it makes sense to expand the capability of a design to a response surface method (RSM). The most common response surface design is the central composite design (CCD) which is a block of factorial runs with center points, plus a block of axial runs with center points that will help find the cause for the curvature and fit a model with quadratic terms. This model, if it is a good and useful model (yours were good) can then be used to optimize a response.

Once an optimal setting is found, a small confirmation experiment should be conducted at and around that point.

(Learn more about design augmentation by attending the two-day computer-intensive workshop "Response Surface Methods for Process Optimization." See for a complete description. Link from this page to the course outline and schedule. Then, if you like, enroll online.)


3. Webinar Alert: 2nd Encore of DOE Made Easy and More Powerful via Design-Expert Software, Part 2—Response Surface Methods (RSM) for Process Optimization (at a time convenient for Europe)

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 again present the second of this series of free webinars by working through case studies on RSM on Tuesday, September 21 at 7 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, via 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 (see

*(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. Events Alert: Practical aspects of algorithmic design of physical experiments from an engineer’s perspective

(2nd Notice) Shari Kraber will present a talk on "Optimal Mixture Design of Experiments for QbD" and represent Stat-Ease at the Annual Conference of the European Network of Business and Industrial Statistics (ENBIS) in Antwerp, Belgium on September 13-15. For more information on this stimulating get-together, see

Pat Whitcomb will also detail "Optimal Mixture Design of Experiments for QbD," but on this side of the Atlantic. His talk will be given for the American Institute of Chemical Engineers (AIChE) Annual Meeting in Salt Lake City, UT, November 7-12. See

Prior to that Pat presents "Practical Aspects of Algorithmic Design of Physical Experiments From an Engineer’s Perspective" for the 54th Annual Fall Technical Conference in Birmingham, AL, on October 7-8. Details for this meeting of quality experts and statisticians are posted at

Also, we invite attendees of the Minneapolis MD&M (Medical Device & Manufacturing) on October 13-14 to visit us at booth #729. If you have not seen Design-Expert version 8 yet, ask for a demonstration.

Click for a list of upcoming appearances by Stat-Ease professionals. We hope to see you sometime in the near future!


5. 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 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.

—> Experiment Design Made Easy (EDME)
(Detailed at
> September 14-15
> November 3-4
> December 7-8*

—> Response Surface Methods for Process Optimization (RSM)
> December 9-10*

* Take both EDME and RSM in December to earn $395 off the combined

—> Basic Statistics for DOE (SDOE)
> September 28**

—> Designed Experiments for Life Sciences (DELS)
> September 29-30**

** Attend both SDOE and DELS to save $295 in overall cost.

—> Mixture Design for Optimal Formulations (MIX)
> October 26-27***

—> Advanced Formulations: Combining Mixture & Process Variables
(MIX2) (
> October 28-29***

*** Take both MIX and MIX2 to earn $395 off the combined tuition!

See 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


I hope you learned something from this issue. Address your general questions and comments to me at:




Mark J. Anderson, PE, CQE
Principal, Stat-Ease, Inc. (
2021 East Hennepin Avenue, Suite 480
Minneapolis, Minnesota 55413 USA

PS. Quote for the month—An amusing example of being un-clear on cause-and-effect relationships:

A 2-year-old going to the lake for the first time with his grandparents saw a water skier and said "Grandma, look at that man chasing the boat!"

—Source: St. Paul Pioneer Press, Bulletin Board, 6/14/10

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 (see for resumes)
—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!


Interested in previous FAQ DOE Alert e-mail newsletters?
To view a past issue, choose it below.

#1 Mar 01, #2 Apr 01, #3 May 01, #4 Jun 01, #5 Jul 01 , #6 Aug 01, #7 Sep 01, #8 Oct 01, #9 Nov 01, #10 Dec 01, #2-1 Jan 02, #2-2 Feb 02, #2-3 Mar 02, #2-4 Apr 02, #2-5 May 02, #2-6 Jun 02, #2-7 Jul 02, #2-8 Aug 02, #2-9 Sep 02, #2-10 Oct 02, #2-11 Nov 02, #2-12 Dec 02, #3-1 Jan 03, #3-2 Feb 03, #3-3 Mar 03, #3-4 Apr 03, #3-5 May 03, #3-6 Jun 03, #3-7 Jul 03, #3-8 Aug 03, #3-9 Sep 03 #3-10 Oct 03, #3-11 Nov 03, #3-12 Dec 03, #4-1 Jan 04, #4-2 Feb 04, #4-3 Mar 04, #4-4 Apr 04, #4-5 May 04, #4-6 Jun 04, #4-7 Jul 04, #4-8 Aug 04, #4-9 Sep 04, #4-10 Oct 04, #4-11 Nov 04, #4-12 Dec 04, #5-1 Jan 05, #5-2 Feb 05, #5-3 Mar 05, #5-4 Apr 05, #5-5 May 05, #5-6 Jun 05, #5-7 Jul 05, #5-8 Aug 05, #5-9 Sep 05, #5-10 Oct 05, #5-11 Nov 05, #5-12 Dec 05, #6-01 Jan 06, #6-02 Feb 06, #6-03 Mar 06, #6-4 Apr 06, #6-5 May 06, #6-6 Jun 06, #6-7 Jul 06, #6-8 Aug 06, #6-9 Sep 06, #6-10 Oct 06, #6-11 Nov 06, #6-12 Dec 06, #7-1 Jan 07, #7-2 Feb 07, #7-3 Mar 07, #7-4 Apr 07, #7-5 May 07, #7-6 Jun 07, #7-7 Jul 07, #7-8 Aug 07, #7-9 Sep 07, #7-10 Oct 07, #7-11 Nov 07, #7-12 Dec 07, #8-1 Jan 08, #8-2 Feb 08, #8-3 Mar 08, #8-4 Apr 08, #8-5 May 08, #8-6 June 08, #8-7 July 08, #8-8 Aug 08, #8-9 Sep 08, #8-10 Oct 08, #8-11 Nov 08, #8-12 Dec 08, #9-01 Jan 09, #9-02 Feb 09, #9-03 Mar 09, #9-04 Apr 09, #9-05 May 09, #9-06 June 09, #9-07 July 09, #9-08 Aug 09, #9-09 Sep 09, #9-10 Oct 09, #9-11 Nov 09, #9-12 Dec 09, #10-1 Jan 10, #10-2 Feb 10, #10-3 Mar 10, #10-4 April 10, #10-5 May 10, #10-6 June 10, #10-7 July 10, #10-8 Aug 10, #10-9 Sep 10 (see above)

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