The term refers to the amount of variability in a given set of data: whether the data points are all clustered together, or very spread out. The unit of measurement usually given when talking about statistical significance is the standard deviation, expressed with the lowercase Greek letter sigma (σ). 10 applications would need to be corrected during the entire year. Six Sigma quality – Six Sigma performance produces a defect-free product 99.99966% of the time allowing only 3.4 errors per one million opportunities.
