Issue: Volume 10, Number 5 (Circulation: Over 5500 worldwide)
Date: May 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,* (-> new web site!), and see a number of new blogs (listed below, beginning with the most recent one):

- Kindergarteners pointing fingers for good (math) or bad (gunning for teacher)
- Over-reacting to month-to-month economic statistics
- A wonderful pairing: Baseball and statistics
- Creativity defeats sensibility for paper helicopter fly-off

Also see the new comments on post #520 (3/28/10): "Misuse of statistics calls into question the credibility of science."

*Need a feed or e-mail updates from StatsMadeEasy? Go to It's easy!

"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: May issue of the Stat-Teaser gives DOE a whirl for making popcorn
2. Software Alert: Version 8.0.2 of Design-Expert released with new feature for Quality by Design (QbD)
3. FAQ: Why run more than one center point in a factorial design?
4. Book Giveaway: 1 copy each of "DOE Simplified, 2nd Ed" (signed) and "Response Surface Methodology"
5. Events Alert: Third European DOE User Meeting (Final Notice)
6. Workshop Alert: See when and where to learn about DOE

P.S. Quote for the month: Discouraging words for those counting on the 2010 census being accurate.

(Page down to the end of this ezine to enjoy the actual quote.)


1. Newsletter Alert: May issue of the Stat-Teaser gives DOE a whirl for making popcorn

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 April issue at It features an article on "Whirley Pop DOE" by the newest addition to our staff of Consultants — Brooks Henderson (check him out at

This Stat-Teaser also details our new two-day, computer-intensive workshop on "Advanced Formulations: Combining Mixture & Process Variables" and it announces the Third European DOE User Meeting in Lucerne, Switzerland. We hope you can make it!

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. Software Alert: Version 8.0.2 of Design-Expert released with new feature for Quality by Design (QbD)

Newly-released version 8.0.2of Design-Expert® software is posted at for free trial evaluation. This web site also provides free patches to update older licensed versions of 8.0.

The new release provides several new features, including this one of particular interest to biopharmaceutical experimenters aiming for Quality by Design (QbD):

=> Graphical optimization now frames the "design space" where all modeled responses fall within confidence, prediction or tolerance intervals (user choice). View the ReadMe file for other features, installation tips, known 'bugs,' change history, and FAQs.


3. FAQ: Why run more than one center point in a factorial design?

-----Original Question-----
Researcher at Nanyang Technological University, Singapore
"You suggested 4 center points for my two-level factorial design. Why are 4 center points required? They are replicates after all."

Answer (from Stat-Ease Consultant Wayne Adams):
"There are several reasons for running multiple center points:
- Provide a sufficiently powerful test for curvature that sets the stage (if it's detected) for augmenting the experiment into a central composite design (CCD) for response surface methods (RSM).*
- Provide a measure of pure error for testing lack of fit
- Stabilize the standard error of prediction in the area of interest if augmented to an RSM-CCD."

*See "Center Points in Central Composite Designs," Pat Whitcomb, June 1998 Stat-Teaser

(Learn more about factorial center points by attending the two-day computer-intensive workshop "Experiment Design Made Easy." See for a description of this class and link from this page to the course outline and schedule. Then, if you like, enroll online.)


4. Book Giveaway: 1 copy each of "DOE Simplified, 2nd Ed" (signed) and "Response Surface Methodology, 3rd Ed"

(Sorry, due to the high cost of shipping, this offer applies only to residents of the United States and Canada.)

Simply reply to this e-mail by May 14 if you'd like (free!) one of two books, possibly blemished slightly:

1. "DOE Simplified, Practical Tools for Effective Experimentation, 2nd edition,"* by Mark J. Anderson and Patrick J. Whitcomb, 2007. (I signed this copy.)
2. "Response Surface Methodology, Process and Product Optimization Using Designed Experiments, 3rd edition," by Raymond H. Myers, Douglas C. Montgomery and Christine Anderson-Cook, 2009.

I will forward your e-mail entries to my assistant Karen. Do not expect to hear from either of us unless your name is drawn as a winner. However, we do appreciate your participation in these giveaways. Watch for more of these in future DOE FAQ Alerts.

Your odds of winning a free book increase by entering each time around!

Reminder: If you reside outside the US or Canada, you are NOT eligible for the drawing because it costs too much to ship the books.

*(This economical and informative how-to softcover primer on factorial design, and its companion "RSM Simplified" are available via e-commerce at


5. Events Alert: Third European DOE User Meeting (Final Notice)

The Third European DOE User Meeting will be held June 1-2 in Lucerne, Switzerland, with pre- and post-conference workshops held on May 31 and June 3. It's sponsored by Stat-Ease, CQ Consultancy (Belgium) and Statcon (Germany). Come to increase your understanding of design of experiments (DOE) techniques, learn of successful real-life applications of DOE, and also attend presentations specific to Stat-Ease software and its features.

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


6. 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.

—> Mixture Design for Optimal Formulations (MIX)
> May 18-19 (Minneapolis)

—> Advanced Formulations: Combining Mixture & Process Variables
(MIX2) (
> May 20-21 (Minneapolis)

(Take both MIX and MIX2 to earn $395 off on combined tuition.)

—> Experiment Design Made Easy (EDME)
(Detailed at
> June 15-16 (Minneapolis, MN)
> July 27-28 (Minneapolis)

—> Response Surface Methods for Process Optimization (RSM)
> July 29-30 (Minneapolis)

(Take both EDME and RSM to earn $395 off on combined tuition.)

—> Designed Experiments for Life Sciences (DELS)
> September 29-30, 2010 (Minneapolis)

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—Discouraging words for those counting on the 2010 census being accurate:

"The government [is] extremely fond of amassing great quantities of statistics. These are raised to the nth degree, the cube roots are extracted, and the results are arranged into elaborate and impressive displays. What must be kept ever in mind, however, is that in every case, the figures are first put down by a village watchman, and he puts down anything he damn well pleases"

—Sir Josiah Stamp (1880 - 1941), British civil servant, industrialist, economist, statistician and banker

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 (see above)

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