Dr Ishikawa stated that the 7 tools of quality will solve 95% of problems in the workplace. From what I have seen over many years, this is very true. Brainstorming alone can bring huge benefits. Simply breaking down the barriers and getting everyone at every level involved in a discussion about a problem, can bring dramatic gains.
By contrast Lean Six Sigma preaches that "green belts" should understand "Mann-Whitney, Kruskal-Wallis, Mood’s Median, Friedman, 1 Sample Sign, 1 Sample Wilcoxon etc" hypothesis testing. This is simply course padding to increase the revenue of con men peddling the Six Sigma Scam. It is of zero value to process improvement.
As statistician Professor Deming pointed out, hypothesis testing is irrelevant to processes because it discards the element of time.
Adding to the ridiculousness is the fact that the above Green Belt hypothesis tests are meant to address non normal distribution paranoia. There is a tool that is far more adept at handling virtually any distribution - the Shewhart Chart!
I wonder just how much saving has ever been achieved by attempting to add such unnecessary complexity, particularly compared to having employees communicate easily?
by Dr Tony Burns BE (Hon 1) PhD (Chem Eng)