Brigadier General

Some answers to your questions...

1. I did do regression on the resulting L12 but thought it too complex for the introductory article. Explaining regression in a short time is non-trivial but I was planning on trying in a later article. We did try very hard to reduce extraneous ...

This page (http://www.sigmazone.com/Taguchi_L12_SpudGun.htm) has a great article on an experiment with a pneumatic spud gun.