The following is a transcript of the infographic above:
The term “Six Sigma” is based on a statistical concept: defective items can be minimized by maintaining 6 standard deviations (6 “sigmas”) between the process mean (average) and its upper and lower specification limits.
Six Sigma also accounts for the tendency of processes to degrade over the long term. A Six Sigma process can tolerate a “shift” of 1.5 standard deviations and still maintain a “safety cushion” between the process mean and its specification limits.