A Bubble Mixture Experiment Project for Use in an Advanced Design of Experiments Class

Abstract

This article gives an example of how student-conducted experiments can enhance a course in the design of experiments. We focus on a project whose aim is to find a good mixture of water, soap and glycerin for making soap bubbles. This project is relatively straightforward to implement and understand. At its most basic level the project introduces students to mixture experiments and general issues in experimental design such as choosing and measuring an appropriate response, selecting a design, the effect of using repeats versus replicates, model building, making predictions, etc. To accommodate more advanced students, the project can be easily enhanced to draw on various areas of statistics, such as generalized linear models, robust design, and optimal design. Therefore it is ideal for a graduate level course as it encourages students to look beyond the basics presented in class.

• Constrained experimental region
• Generalized linear model
• Optimal design
• Poisson regression
• Robust parameter design

Acknowledgments

This research was supported, in part, by the Natural Sciences and Engineering Research Council of Canada. MINITAB is a trademark of Minitab Inc. Joy— and Ivory— are trademarks of Procter and Gamble. The authors would also like to thank two anonymous referees whose insightful comments improved the article.