The core of the Six Sigma methodology is a data-driven, systematic approach
to problem solving, with a focus on customer impact. Statistical tools and
analysis are often useful in the process. However, it is a mistake to view the
core of the Six Sigma methodology as statistics; an acceptable Six Sigma project
can be started with only rudimentary statistical tools.
Still, some professional statisticians criticize Six Sigma because
practitioners have highly varied levels of understanding of the statistics
Six Sigma as a problem-solving approach has traditionally been used in fields
such as business, engineering, and production processes.