Six Sigma in Industry

Sigma (σ) denotes the standard deviation of a population. Six Sigma is the term used in industry to describe a process that has no more than 3.4 defects out of a million. The reference to Six Sigma suggests six standard deviations away from the center of a normal distribution, but the assumption of a perfectly stable process is placed with the assumption of a process that drifts slightly, so the defects per million. This defect rate is so low that defects are considered to be almost eliminated. Adopting the Six Sigma goal of quality, Motorola saved more than $950 million in years. AlliedSignal reported a savings of $1.5 billion. GE, Polaroid, and Texas Instruments are other major companies that have adopted the Six Sigma goal.