Issue: Volume 6, Number 8
Date: August 2006
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, 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: Is something always better than nothing?  For an answer to this tricky question, see

Topics in the body text of this DOE FAQ Alert are headlined below (ones that delve into statistical detail are designated "Expert"):

1. Newsletter alert: The August issue of the Stat-Teaser features a fun, but very sophisticated DOE on the "Cat-a-Pult"
2. Software alert: Version 7.03 updates released
3. FAQ: Design-Ease® versus Design-Expert® software
4. Events alert: Talk/exhibit at Seattle's Joint Stat Meetings
5. Events Alert: See when and where to learn about DOE

PS. Quote for the month: How the famous author Jane Austen generated food for her fascinating writing.


1. Newsletter alert: The August issue of the Stat-Teaser features a fun, but very sophisticated DOE on the "Cat-a-Pult"

Many of you will soon receive or already have 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

This issue of the Stat-Teaser features a fun, but very sophisticated response surface method (RSM) experiment done by Stat-Ease consultant Shari Kraber on the "Cat-a-Pult" made by Hands On Toys.  For a view of this fascinating toy, watch the instructional video at

(Learn more about RSM by attending the three-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.)


2. Software alert: Version 7.03 updates released

If you are a licensed user of Design-Ease or Design-Expert V7 software, please download the free maintenance update to V7.0.3 posted at The new release provides several new features that you see detailed on page 2 of the August 2006 Stat-Teaser (link provided above).


3. FAQ: Design-Ease® versus Design-Expert® software

-----Original Question-----
"Can you briefly explain the differences between Design-Ease (DE) and Design-Expert (DX)?  The website mentions that the main differences are that DX includes 'in-depth analysis of process factors or mixture components.'  What exactly is meant by that?"

Answer (from Stat-Ease Consultant Wayne Adams): "Design-Ease is essentially a 'light' version of Design-Expert software.  Even so, Design-Ease provides a complete array of factorial designs, which reveal main effects at the least and possibly breakthrough interactions of factors.  Perhaps 80% of the problems can be solved with this relatively simple form of DOE. However, when you are ready to optimize your process, then you need Design-Expert, because it offers response surface methods (RSM).  Design-Expert also provides the tools one needs for mixture design and analysis aimed at optimizing formulations."

(See for details about Stat-Ease software.  Link from there to free 45-day fully-functional trials.  Give Design-Ease and/or Design-Expert a try!)


4. Events alert: Talk/exhibit at Seattle's Joint Stat Meetings

Stat-Ease will make an appearance on the West Coast at the Joint Statistical Meetings (JSM) of the American Statistical Association (ASA) and several other professional societies next month in Seattle, WA.  Consultant Wayne Adams will chair a roundtable discussion on "Graphical & Numerical Approaches to Selecting Effects in Two-Level Factorial Models" ( ) over lunch on Tuesday August 8.  It is sponsored by the Section on Quality and Productivity (Q&P).  Stat-Ease will exhibit its software at Booth 318 on Sunday, August 6th through Wednesday the 9th.

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

PS.  Do you need a speaker on DOE for a learning session within your company or technical society at regional or national levels? If so, contact me.  It may not cost you anything if Stat-Ease has a consultant close by.  However, for presentations involving travel, we appreciate reimbursements for airfare, hotel and meals — expenses only.  In any case, it never hurts to ask Stat-Ease for a speaker on this topic — we are at the foremost ranks of practical expertise on design of experiments for process and product improvement.  Contact me at if you have an event coming up with an open slot for a presentation.


5. Workshop alert: See when and where to learn about DOE

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.

*Believe it or not, it only takes a class of 4 students to make it economical for Stat-Ease to come and teach at your site versus sending them out to one of our public presentations.  The economics are detailed in the August 2006 issue of the Stat-Teaser newsletter at .


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 —A philosophical view on how life must be lived that can be readily applied to the problem of understanding processes (and why one must experiment!):
"Life can only be understood backwards, but must be lived forwards."
—Soren Kierkegaard

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
—Stat-Ease consultants Pat Whitcomb, Shari Kraber and Wayne Adams (see for resumes)
—Statistical advisor to Stat-Ease: Dr. Gary Oehlert (
—Stat-Ease programmers, especially Tryg Helseth and Neal Vaughn (
—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, #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 (see above)

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