One of the first assignments in our Black Belt course deals with the origins of the continuous improvement approach that we know today as Six Sigma. Many students are surprised to learn that the body of knowledge and the tools and techniques have been evolving for well over 100 years. This article is the first […]

On January 20th, 2017, **posted in:** Articles, Six Sigma by Roger EllisTags: quality pioneers, Six Sigma

The Six Sigma methodology relies on decisions that are made based on facts and data. One of the challenges in the Analyze phase of Six Sigma is being able to identify what is really going on in a process based on the facts and data that were collected in the Measure phase. Another challenge is […]

On September 4th, 2016, **posted in:** Articles, Six Sigma by Roger EllisTags: data analysis, sabermetrics, Six Sigma

One of my Black Belt students recently submitted his final project report. He used the two proportions test in Minitab to compare the proportion of on time performance for completion of employee appraisals, before and after improvement. I sent him the following feedback regarding this test. “Hi. Your null and alternate hypotheses are correctly stated. […]

Although the central limit theorem can seem abstract and devoid of any practical application, this theorem is actually quite important to the practice of statistics. As we will see, this theorem allows us to make some assumptions about a population. In order to understand the basis for the Central Limit Theorem, consider a population of […]

On June 16th, 2016, **posted in:** Articles, Six Sigma by Roger EllisTags: Central Limit Theorem, Six Sigma