Most industries today recognize Six Sigma as a standard means to accomplish process and quality improvements. The process that led to Six Sigma was originated in the 19th Century with the bell curve developed by Carl Friedrich Gauss. In the 1920s, statistician Carl Shewhart, a founding member of the Institute of Mathematical Statistics, showed that a process required correction after it had deviated Three Sigma from the mean. Six Sigma refers to having six standard deviations between the mean of the actual performance of a process and the expected performance limits of the process. That translates to a 0.999997 probability (99.9997%) that the process performance is as desired, or to fewer than 3.4 Defects per one Million Opportunities (DPMO).