the symbol (σ) is used to indicate one standard deviation from the mean, particularly in a normal distribution
sigma is the sum-of-divisors function; sigma(n) is the sum of all the positive integers dividing n A generalization is sigma_k(n), the sum of all the kth powers of the divisors of n sigma_k, and thus sigma = sigma_1, is a multiplicative function
Any of three unstable subatomic particles in the baryon family, having a mass 2,328 to 2,343 times that of the electron and a positive, neutral, or negative electron charge
A methodology that provides businesses with the tools to improve the capability of their business processes This increase in performance and decrease in process variation lead to defect reduction and improvement in profits, employee morale and quality of product
Systematic quality program that strives for 6 standard deviations between the mean and the nearest specification limit In extremely high quality processes, rejects will be the smallest of the Six Big Losses
A movement, method and set of techniques focused on improving business processes Relies heavily on statistical techniques to measure success There are multiple Six Sigma methods, some designed for process improvement and some for designing or redesigning business processes Most Six Sigma books, however, emphasize incremental process improvement Often associated with Mikel Harry and Motorola
Literally, refers to the reduction of errors to six standard deviations from the mean value of a process output or task opportunities, i e about 1 error in 300,000 opportunities In modern practice, this terminology has been applied to a quality improvement methodology for industry
A process that is six sigma generates a maximum defect probability of 3 4 parts per million (PPM) when the amount of process shifts and drifts are controlled over the long term to less than +1 5 standard deviations from the centered mean
Literally, it means six standard deviations from the mean or median value As applied to quality metrics, the term indicates that failures are at least six standard deviations from the mean or norm This would mean about 3 4 failures per million opportunities for failure For more detail, please visit the iSixSigma website
A quality measure and improvement program developed by Motorola that focuses on the control of a process to the point of ± six sigma (standard deviations) from a centerline, or 3 4 defects per million items It includes identifying factors critical to quality as determined by the customer, reducing process variation and improving capabilities, increasing stability and designing systems to support the six sigma goal