Overdispersion of data

One of my Master Black Belt students sent me an inquiry about a manufacturing process that was producing a very small percentage of scrap.  He was having trouble understanding the control charts that he had created from his data and was convinced that he needed to perform a transformation on the underlying data. I started […] read more

On July 20th, 2016, posted in: Project Management by

Issues in sampling – a real world example

In a previous article in this series I discussed issues to be aware of when selecting a sample from a larger population. You may find it useful to review that article before reading this one. Samples must be randomly selected in order to be representative of the overall population. Otherwise, we risk introducing bias into […] read more

On January 16th, 2016, posted in: Project Management by

Is Six Sigma the only way to improve?

When training and coaching Six Sigma professionals, one of the topics that I encourage folks to think about is whether or not Six Sigma is the only path that should be followed by an organization that is seeking to improve their operations.  In our Green Belt program I ask students to choose one side or […] read more

On July 8th, 2015, posted in: Project Management by

Statistical Software – A Trap for the Unwary

Statistical software is widely used in practice to conduct various statistical tests and to generate various graphs and charts.  In our Six Sigma courses we use Minitab, which has been under continuous development since 1972 and is one of the most widely used statistics packages.  There are many other fine products on the market as […] read more

On May 15th, 2015, posted in: Project Management by Tags: ,