Which of the following statements about Six Sigma measurement is true?

The statement indicating that the Six Sigma definition of sigma is different from the sigma of control charting is accurate because Six Sigma and control chart sigma have different contexts and implications. In Six Sigma methodology, sigma refers specifically to the process capability, which is driven by the number of defects per million opportunities (DPMO) and relates to the overall quality level of a process. This sigma is a reflection of how much variation exists in the process concerning customer requirements.

On the other hand, sigma in control charts, which are used in statistical process control (SPC), typically relates to the natural variability within a process and is often used to determine control limits. While both concepts deal with variability, they serve different purposes within quality management practices. Thus, the interpretation of what sigma represents in the context of Six Sigma can be distinct from its traditional use in statistical control, making this statement true.

Understanding these nuances can significantly impact how a company approaches quality improvement and process management in its operations.