Jun 30 2022
A Kaizen Case Study
This is the start of a new section of this blog, about case studies. The stories do not have to be extraordinary but they have to be real, from factories large and small. The Japanese example below is a manga. It’s a difficult art, and I am not expecting anyone to submit cases in this form. An infographic showing before and after states, methods used, and results achieved would be plenty. I will then format it for this blog and post it in this category.
Jul 18 2022
The Most Basic Problem in Quality
Two groups of parts are supposed to be identical in quality: they have the same item number and are made to the same specs, at different times in the same production lines, at the same time in different lines, or by different suppliers.
One group may be larger than the other, and both may contain defectives. Is the difference in fraction defectives between the two groups a fluctuation or does it have a cause you need to investigate? It’s as basic a question as it gets, but it’s a real problem, with solutions that aren’t quite as obvious as one might expect. We review several methods that have evolved over the years with information technology.
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By Michel Baudin • Data science • 0 • Tags: A/B testing, Barnard's Test, Binomial Probability Paper, Fisher's Test, Incoming QA, Z-test