Issue: Volume 6, Number 2
Date: February 2006
From: Mark J. Anderson, Stat-Ease, Inc. (http://www.statease.com)

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 http://www.statease.com/doealertreg.html. If this newsletter prompts you to ask your own questions about DOE, please address them via mail to:[email protected].

This plain text message may be easier to read if you do not remove the line breaks. If you use Microsoft Outlook, press the bar labeled "Extra line breaks in this message were removed." In newer versions select "Restore line breaks."

Here's an appetizer to get this Alert off to a good start: A photo of the wondrous Ferris Wheel at the 1893 Chicago World’s Fair http://www.randomhouse.com/crown/devilinthewhitecity/ferris.html which I came across while reading a great book—"The Devil in the White City" by Erik Larson. According to the web site posted by the publisher (Random House), this 250-foot diameter wheel carried 36 cars holding 60 riders each (2160 people total!). It was supported by two 140-foot steel towers connected by a 45-foot axle—the largest single piece of forged steel ever made at the time. This original Ferris wheel moved on to another location before being scrapped after the turn of the century. A hundred years later the London Eye became the sensation for this millennium. The operators distinguish their wheel from Ferris's because its capsules are enclosed, positioned on the outside and supported by an A-Frame. On a beautiful cloudless day without a breath of wind, I waited in line to get on the Eye when I was last in London, but it then closed down due to high temperatures (80 degrees F) and the greenhouse warming within its 32 glassy capsules. John H. Lienhard, Professor Emeritus of Mechanical Engineering and History at the University of Houston, reports that the Eye carries up to 800 people (25 per capsule) through one 30 minute rotation—far less than that of Ferris's Wheel over a century before. For Professor Lienhard's report on the London Eye, including photos, see http://www.uh.edu/engines/epi1923.htm.

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

1. FAQ: Variations in how r-squared is calculated
2. Response to Stat-Teaser quote: Not so simple
3. Tutorial alert: Five new guided tours of features offered in version 7 (new!) of Design-Expert® software
4. Winners of free books (US/Canada only): Drawing for two copies of Montgomery's "Design and Analysis of Experiments" (5th Edition) plus "DOE Simplified" and "RSM Simplified" (both books autographed by authors Anderson and Whitcomb)
5. Events alert: First European DOE User Meeting for Design-Expert and Design-Ease Users, Belgium, April 24-25
6. Workshop alert: See when and where to learn about DOE

PS. Quote for the month: Wise words on experimental design by Box, Hunter and Hunter from their new edition of "Statistics for Experimenters."

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1. FAQ: Variations in how r-squared is calculated

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

PLEASE DO NOT SEND ME REQUESTS TO SUBSCRIBE OR UNSUBSCRIBE—FOLLOW THE INSTRUCTIONS AT THE END OF THIS MESSAGE.

Sincerely,

Mark

Mark J. Anderson, PE, CQE
Principal, Stat-Ease, Inc. (http://www.statease.com)
2021 East Hennepin Avenue, Suite 480
Minneapolis, Minnesota 55413 USA

PS. Quote for the month—Wise words on experimental design by Box, Hunter and Hunter from their new edition of "Statistics for Experimenters":

"When your television set misbehaves, you may discover that a kick in the right place often fixes the problem, at least temporarily. However, for a long-term solution the reason for the fault must be discovered. In general, problems can be fixed or they may be solved. Experimental design catalyzes both fixing and solving."

—"Statistics for Experimenters: Design, Innovation, and Discovery, 2nd Edition" by George E. P. Box, J. Stuart Hunter, William G. Hunter, June 2005, John Wiley & Sons, New York.

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, Shari Kraber and Wayne Adams (see http://www.statease.com/consult.html for resumes)
—Statistical advisor to Stat-Ease: Dr. Gary Oehlert (http://www.statease.com/garyoehl.html)
—Stat-Ease programmers, especially Tryg Helseth and Neal Vaughn (http://www.statease.com/pgmstaff.html)
—Heidi Hansel, Stat-Ease marketing director, and all the remaining staff

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#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 (see above)

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