“what percentage of a normal distribution is contained within six sigma?”
approx. 99.9999999009878 %
”how many sigma are there?”
I’m not sure what you mean with this question. How many sigma are there where?
”what is the difference between six sigma projects and poka-yoke error proofing. poka-yoke seems to be for creating zero defect product, and six sigma for reducing the amount of nonconforming product through discipline and study. can someone give me some examples of different industries or products that would be clearly a subject of error-proofing or alternately six sigma?”
Six Sigma is the realization/recognition of upper management that customer oriented quality is important. Six Sigma emphasizes a disciplined data oriented approach to problem solving (DMAIC/DMADV methodologies). In application the emphasis is on meaningful metrics, a common language, training at all levels of an organization and a team approach to problem solving. Six Sigma incorporates other methodologies/tools such as QFD/Poke-Yoke/Lean. As a methodology it is applicable to any process, and it’s use is expanding beyond manufacturing and transactional business applications to government, schools and hospitals. I believe that you would use at least some of the Six Sigma methodology (Define/Measure/Analyze/Improve/Control) prior to implementing a poka-yoke solution. It would be up to you and your company when to use what tool. I would just caution you to use what is practical for a given situation.