Issue: Volume 5, Number 12
Date: December 2005
From: Mark J. Anderson, Stat-Ease, Inc. (

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, please click on the links at the bottom of this page. If you have a question that needs answering, click the Search tab and enter the key words. This finds not only answers from previous Alerts, but also other documents posted to the Stat-Ease web 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

Here's an appetizer to get this Alert off to a good start:

Details on the Ebbinghaus "Forgetting" Curve at and a picture of the author and his remember-ability plot at (shortcut* to a page at I forget how I heard about Ebbinghaus (it escapes me!), but I've been saying to my DOE students for years that they might enjoy a memory half-life of a week at best for the material presented in class. In other words, half of what they learn will be forgotten in a 7 days and most of it gone in a month. However, it's been found that by repeated review and practice, details can be remembered for a much longer period of time. Therefore, to make the most of what you learn about a powerful tool like design of experiments, just do it!

On a lighter note (literally!), my son Hank (a programmer for Stat-Ease) passed along this heads-up (literally!) on colored bubbles invented by a fellow resident of our Twin Cities (Saint Paul and Minneapolis) in Minnesota: (shortcut* to a page at Click the link to "Ascadia Zubbles" for more pictures and details of these amazing-looking "zubbles"—touted at There you will find a two-minute video to brighten your dreary day. Why didn't I think of this? See my mixture design on a home recipe for do-it-yourself bubbles (not colored, unfortunately), at

*[As you may have noticed, I now use to make long links shorter. A DOE FAQ Alert reader suggested this—thanks! If any of you find this markedly better or worse than what I used before, let me know. —Mark]

Here's what I cover in the body text of this DOE FAQ Alert (topics that delve into statistical detail are designated "Expert"):

1. Newsletter alert: December issue of the Stat-Teaser features writeup on ruggedness testing, plus details on V7 release of Design-Expert® software, including an order form
2. Software alert: Design-Ease® version 7 now in beta release—Needed: A few good testers
3. Info Alert: A "da Vinci approach" to sensory development
4. Events alert: Design for Six Sigma (DFSS) conference
5. Workshop alert: California workshops on DOE (2nd notice)

PS. Quote for the month: Da Vinci's warning about experimental bias.


1. Newsletter alert: December issue of the Stat-Teaser features writeup on ruggedness testing, plus details on V7 release of Design-Expert® software, including an order form

Many of you will soon receive 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 December issue at

The feature article, "Struggle for Power vs. Resolution vs. Simplicity in an ASTM Standard," tells how I helped upgrade the strategy of experimentation specified in E1169 for Ruggedness Testing. This may be of particular interest to those in regulated industries who must be concerned with validation of their products and processes.

Also in this issue of the Stat-Teaser you will find details on the new release of Design-Expert software, along with a handy order form that can be faxed in to purchase new licenses or economical upgrades.


2. Software alert: Design-Ease® version 7 now in beta release—Needed: A few good testers

Our programmers turned off the high-end response surface methods and mixture design features in Design-Expert version 7 (DX7) software to create a simpler and easier-to-use Design-Ease (DE7). This program finds favor with those for whom experimentation is not second nature, for example those tasked with Six Sigma process improvements in non-manufacturing areas such as marketing or administrative transactions.

In any case, if any of you readers can spare some time to take a look at DE7-beta, send me an e-mail requesting the link for the download and associated tutorials. —


3. Info alert: A "Da Vinci approach" to sensory development

Dr. Mathias Sucan, an independent consultant, attended our recent presentation of Mixture Design for Optimal Formulations. He provided the following 'heads-up': "As a user, I have been a big promoter of Design-Expert everywhere I have worked, where I successfully used it to optimize numerous formulas that sold for several millions of dollars. I learned to use the software as a tool, and to call on it at the right time during the course of product development. I integrated my experience with your software in a recent article on flavor development entitled 'The da Vinci Approach' in the May 2005 issue of Perfumer & Flavorist."

See this article at or order it directly from the publisher via a link found at


4. Events alert: Design for Six Sigma (DFSS) conference

We will attend and display our software at the Design for Six Sigma conference, January 16-18, 2006, in Memphis, Tennessee. Among the speakers are several (probably more that I missed or don't know of) clients of Stat-Ease software and training resources:
- (Keynoter) Martha Gardner, Global Quality Leader, Global Research, General Electric Company (GE),
- Kevin Ward, Director R&D Design Systems, and Dan Kussman, Master Black Belt, both from Boston Scientific.

The lineup of top people and their companies is quite impressive as you will see at the conference web site:

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


5. Workshop alert: California workshops on DOE (2nd notice)

Stat-Ease makes its annual escape from the cold Minnesota winter with two presentations of Experiment Design Made Easy in California:
- Anaheim, December 6-8
- San Jose, January 10-12.

Do not delay: Enroll as soon as possible for these rare appearances on the West Coast.

See for 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 Stat-Ease at 1.612.378.9449. 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. Call us to get a quote.


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—Da Vinci's warning about experimental bias:

"Experience does not ever err; it is only your judgment that errs in promising itself results which are not caused by your experiments."

—Leonardo da Vinci
(For "eye"lightenment on this famous scientist/artist see Boston's Museum of Science site at From there I advise you click the link labeled "Renaissance Man".)

Trademarks: Design-Ease, Design-Expert and Stat-Ease are registered trademarks of Stat-Ease, Inc.

Acknowledgements to contributors:
—Students of Stat-Ease training and users of Stat-Ease software
—Fellow Stat-Ease consultants Pat Whitcomb and Shari Kraber (see for resumes)
—Statistical advisor to Stat-Ease: Dr. Gary Oehlert (
—Stat-Ease programmers, especially Tryg Helseth (
—Heidi Hansel, Stat-Ease marketing director, and all the remaining staff


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 (see above)

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