Six Sigma Quality
The ultimate goal of quality programs at companies such as Motorola, Honeywell, and General Electric is to achieve Six Sigma quality. This means that the process is so well understood and tightly controlled that the mean defect rate, µ, and the standard deviation, ó, are both very small. As a result, the upper and lower control limits in Exhibit 19-3 can be set at a distance of 6ó (six sigma) from the mean (µ) . The implication of controlling a process at a Six Sigma level is that the process produces only 3.4 defects per million products produces.