Vol. 24, No. 4 - July/August 2024

IN THIS ISSUE: misleading main effect graphs, “DOE It Yourself,” a Clerihew, and more

FAQ

Working a substitute material into a mixture design for optimal formulations

Original question from a Data Science Consultant:
“It was interesting to attend session one of your Modern DOE workshop today. I’m looking forward to the rest of the week. I have a follow-up about two-level factorial popcorn case study with its big interaction of time and power—factors B and C; respectively. When I look at terms B or C individually under Model Graphs, the program warns me that the factor is involved in the BC interaction. Is it a big mistake to look much at individual factors when there is a significant interaction?”

Answer:
Yes, it’s misleading to look at main effects involved in an interaction because they depend on another factor. For example, increasing time does decrease taste. However, this factor (B: Time) only creates a significant effect at high power (C+)—at low power (C−) changing time over the range tested did not have a significant impact. This becomes clear only by viewing the BC interaction plot* and paying heed to the least-significant-difference (LSD) bars—them overlapping at low power (C−) and exhibiting a big separation at high power (C+).

*See Figure 1 in my article “Popcorn Experiment Remains Fresh for Featuring Factorial Screening.”

(Learn more about interactions by enrolling in the next Designed Experiments for Biotech & Pharma or Modern DOE for Process Optimization workshop.)

EVENTS

On September 18 at 2 pm Central US Time (CT) I will present a webinar on “Common Mistakes in Experimental Design (DOE nots!)” for the International Society of Six Sigma Professionals (ISSSP). Based on 50 years of experience doing statistically designed experiments, I will lay out a long list of causes for DOE failures. Learn from my mistakes and those of Stat-Ease clients! Register here.

On September 25 at 10 am CT join me for an educational on-line session on “DOE for on-target results with minimal variation”. This presentation makes the case for modeling both mean and standard deviation. It demonstrates benefits via examples where experimenters took advantage of making multiple measurements for every run in their design. Newcomers to statistical design of experiments (DOE) often overlook this opportunity to achieve more robust operating conditions. Attend this webinar to master DOEs aimed at meeting specifications and doing so with utmost reliability. Sign up here.

Click here to view the complete list of Stat-Ease events.

Do you need a speaker on DOE for a learning session within your company or professional society at regional, national, or international levels? If so, please get back to me.

ONLINE LEARNING

Sharpen up your DOE skills with a mix of free and paid training: whatever fits your business needs.

Comprehensive DOE courses — Online instructor-led learning

• Designed Experiments for Biotech & Pharma 5 half-days, $1255: September 16-20

• Mixture Design for Optimal Formulations 4 half-days, $1155: October 28-31

• Modern DOE for Process Optimization 5 half-days, $1255: December 9-13

  
  

See this web page for the complete schedule of upcoming Stat-Ease courses. To enroll in the workshop that suits you best, click Register on that webpage, or click here to contact us.

If you lead a group of six or more colleagues, save money and customize content via a private workshop. For a quote, please contact us.

Free webinars — Sign up to take advantage

• Wednesday, August 21, 10 am CT—Robustness studies: If anything can go wrong, prevent it! by Richard Williams

• Wednesday, September 25, 10 am CT— DOE for on-target results with minimal variation by me

Click here to view the times, descriptions and registration links for all upcoming live webinars. Sign up now to advance your DOE know-how!

On-Demand Videos

By the way, our Statistics Made Easy By Stat-Ease YouTube channel provides a free library of highly educational recorded webinars covering a wide variety of DOE tools. It offers videos at all levels—from those new to DOE on up. Take advantage!

INFO

The April 2024 issue of The Journal of Plastic Film and Sheeting features a heads-up by me to Know the SCOR for a winning strategy of experimentation. They granted open access to my writeup, so take advantage!

Also, check out my newly updated DOE It Yourself—a long list of fun and educational science projects for children and/or adults, all of which demonstrate the value of design of experiments. If you try any of my suggestions or come up with a new one, get back to me with the outcome and tips for others who enjoy DIY DOEs to do at home or in class.

BLOG

StatsMadeEasy

My wry look at all things statistical and/or scientific with an engineering perspective.

• Common confusion about probability can be a life or death matter

• Coin-flip hack: How to call it—heads or tails—to improve your odds

• Design of experiments (DOE): Secret weapon for model rocketry

Stat-Ease Blog

Great tips from the Stat-Ease team for making DOE easy, for example, this recent post by me on Tips and tools for modeling counts most precisely.

Feel free to get back to me via [email protected] with further questions or comments: I would really appreciate hearing from you!

All the best,

Mark J. Anderson, PE, CQE, MBA
Engineering Consultant, Stat-Ease, Inc.
www.linkedin.com/in/markstat/

QUOTE OF THE DAY

“William Sealy Gosset
turned on the faucet,
sampled the beer:
law of error got clear.”

— Larry Lesser (composed in a poetic form called a Clerihew and published in the April 2024 issue of the Amstat News)

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