Issue: Volume 1, Number 7
Date: September, 2001
From: Mark J. Anderson, Stat-Ease, Inc.
Here's another set of frequently asked questions (FAQs) about doing design of experiments (DOE), plus alerts to timely information and free software updates. Feel free to forward this newsletter to your colleagues. They can subscribe by going to: http://www.statease.com/doealertreg.html.
Summer is slipping away here in the northern part of the USA, so we treasure every sunny, warm day. With these thoughts in mind, I offer the following links as appetizers. First of all, check out: http://www.formulasun.org/asc/aboutasc/history/asc2001/index.html. It reveals the 2001 winner of The American Solar Challenge, a cross-country solar car race that runs along old Route 66 from Chicago, Illinois, to Claremont, California. My alma mater, the University of Minnesota, placed sixth in the race. Secondly, to shed light on what makes stock markets go up, see http://www.osu.edu/researchnews/archive/sunstock.htm.
Here's what I cover in the body text
of this DOE FAQ Alert:
1. FAQ: Applying response transformations recommended by the Box-Cox plot
2. Alert: Upgrade patches available for V6.05 of Design-Expert® (DX) and Design-Ease® (DE) software
3. User feedback: Loading the DX User Guide onto a Palm PC
4. Info alert: See the new issue of the Stat-Teaser newsletter
5. Reader feedback: Publish your DOE success story
6. Events alert: A heads-up on DOE talks and demos
7. Workshop alert: "Real-Life DOE - Tricks of the Trade"
PS. Quote for the month - a statistical lament (forwarded by a reader)
1 - FAQ: Applying response transformations recommended by the Box-Cox plot
From: North Carolina
"I have recently downloaded Design-Expert as a demo. I love the software and wonder how I ever lived without it! However, I do have some questions. Sometimes I get a recommendation in the Box-Cox plot that can't be implemented...more precisely, I can make the change in the model, but it doesn't effect the "recommendation" upon re-running the model."
(To see a picture of Design-Expert's Box-Cox plot and a brief explanation, refer to page 3-13 in the User Guide (view this at http://www.statease.com/x6ug/DX03-Factorial-Levels-Two.pdf.) Doug Montgomery provides details on the Box-Cox plot, with output from Design-Expert shown as illustration, in Section 14-1.1 (pages 590-593) of his textbook, "Design and Analysis of Experiments," 5th edition, which you can purchase from the Stat-Ease site at http://www.statease.com/prodbook.html.)
(By Pat Whitcomb)
"If the Box-Cox plot recommends a transformation, for example a logarithm (Log), and you try it, and then come back to the Box-Cox plot, and it still recommends the same transformation (in this case a Log), you are done. If taking the log changes the selected model sufficiently, the Box-Cox plot could recommend a different transform, for example: a square root (sqrt). In this case the recommended (sqrt) and current (Log) differ, so you would then want to try modeling using the sqrt transform."
(Learn more about the Box-Cox plot and response transformations by attending the 3-day computer-intensive workshop "Experiment Design Made Easy." Go to http://www.statease.com/clasedme.html for a description and links to the course outline, schedule and on-line registration.)
2 - Upgrade patches available for V6.05 of Design-Expert or Design-Ease software
If you (as an individual user) own a permanently licensed copy of version 6 of Design-Ease (DE6) or Design-Expert (DX6), go to http://www.statease.com/soft_ftp.html#dx6updt for downloads that will patch your (individual-license only) software with the latest enhancements. We recommend you do this even though the changes may affect only a few users. To see what got added or fixed, click the "Read Me" link for either DE or DX (whichever program you will be updating).
Call Stat-Ease customer service at 1.612.378.9449 if you own networked software that needs updating. Be prepared to provide your serial number. They will arrange to send you a replacement CD-ROM to re-install on your network.
Before updating or buying version 6 of Design-Expert, feel free to download a fully-functional, but 30-day limited, version of the software from http://www.statease.com/dx6trial.html. Users of Design-Ease or earlier versions of Design-Expert (V5 or before) should consider upgrading their software to DX6. See why you should do it at http://www.statease.com/dx6descr.html. Then call Stat-Ease for a quote. After validating your current serial number, they will give you a special upgrade price.
3 - User feedback: Loading the DX User Guide onto a Palm PC
From: A Design-Expert software user in Illinois
"I would like to carry the manual in my palm for reference. In order for me to be able to do that it would be ideal to get a PDF [(Portable Document Format] generated using Adobe Acrobat 5.0. Please let me know when you upgrade it."
As requested, I upgraded my copy of Adobe Acrobat and re-distilled all sections of the Design-Expert User Guide. These are posted at http://www.statease.com/dx6_man.html for anyone to download. To read the files, we recommend Acrobat Reader 5.0, or higher, which you can download from Adobe at http://www.adobe.com.
I was very pleased with how well the new version of Acrobat integrated with my Microsoft Word 2000. It's now much easier to produce PDF files.
4 - Info alert: See the new issue of the Stat-Teaser newsletter
If you did not get a printed copy, see the latest Stat-Teaser newsletter by clicking the link labelled "September 2001" at http://www.statease.com/newsltr.html. The feature article is "Bread DOE Part 2: Semifold Confirms Cause for Failure." It's very interesting, if I do say so myself (I am the author). The newsletter also offers an inspiring case study entitled "3M Enhances SPE Disk Performance with DOE." Check it out if you've not done so already.
5 - Reader feedback: Publish your DOE success story
Many of you have taken advantage of the reprints we offer at http://www.statease.com/casestud.html. If not, feel free to do so. In return we ask that you contribute your DOE success story as inspiration to your professional colleagues. If you benefitted by using Stat-Ease software, we can offer the services of professional writers to develop and place your story as a case study. This benefits us, you and your company as well as the readers - so everyone comes out ahead. Let me know if you think you've got a good success story and I will arrange for follow-up.
I'd be pleased to get contributions
from any quarter, but especially those that relate to these specific requests
from editors of the following trade-publications:
- "Adhesives for Engineers" book due out next March
- "Paint and Coatings Industry" for publication this Fall to continue a series that's been published on DOE.
6 - Events alert: A heads-up on DOE talks and demos.
Click http://www.statease.com/events.html for a listing of where Stat-Ease consultants will be giving talks and doing DOE demos. We hope to see you sometime in the near future!
I mentioned this in my last Alert,
but it bears repeating: We will exhibit our software and training materials
at the Fall Technical Conference (FTC) in Toronto on October 18-19. I highly
recommend the FTC for those of you advanced practitioners who want to broaden
your knowledge of applied statistical tools, including DOE. For all the details,
including a registration form go to http://www.amstat.org/sections/spes/
and click on the link labelled "Fall Technical".
7 - Workshop alert: "Real-Life DOE - Tricks of the Trade"
As of now we've only got a few students
signed up for our "Real-Life DOE: Tricks of the Trade" workshop, which
will be presented on September 18-19. My partner Pat Whitcomb says he will not
cancel his presentation of this class so long as even one person signs up, so
it may be an unusually good time to attend and get some personal attention from
an expert practitioner. See http://www.statease.com/rldoe.html
for an overview of the class and links to the outline and online registration.
This workshop is intended for people who do DOE very well, but would like to
improve their skills. Factorial design experience is a must. If you need the
basics, attend our Experiment Design Made Easy
Also, as noted in my previous Alert,
our new 2-day "Statistics for Technical Professionals" workshop debuts
October 30-31 in Minneapolis. Despite the conjunction of this presentation with
Halloween, we do not intend to scare attendees with statistics. In fact we hope
to do just the opposite: Show engineers, scientists and quality professionals
how to gear up their stats knowledge to achieve Six Sigma objectives or other
quality improvement initiatives. See http://www.statease.com/clas_stp.html
for all the details. To enroll, just hit the "register online" link
this page. We hope to see you this Fall. Come as you are - no costume is required.
See http://www.statease.com/clas_pub.html for schedule and site information for all Stat-Ease workshops open to the public. To enroll, 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 questions and comments to me at:
Mark J. Anderson, PE, CQE
Principal, Stat-Ease, Inc. (http://www.statease.com)
Minneapolis, Minnesota USA
PS. Quote for the month - a statistical lament (forwarded by a reader):
is my master, I know nothing.
It makes me lie down amongst expected means,
and leads me deeper into the unknown.
It guides my path of misunderstanding,
for its name sake.
Even as I walk through the valley of covariances,
I fear everything, for I know nothing.
Its degree of freedom and sums of squares
When I do statistics, I prepare
a feast for my enemies.
It anoints my head with frustration,
my blood pressure rises.
Surely confusion and fear will follow me
all the days of my life,
and I will dwell in the house of the
statistically ignorant FOREVER."
- Marvin Hall
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 http://www.statease.com/consult.html 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