Sigma is the term for standard deviation. Six Sigma refers to six steps away from the average. Don’t let the statistical term throw you. There are a few basic concepts required to make use of six sigma. They can be learned by anyone.
If you own a Pizza shop that is open for lunch you must deliver pizza between 11:30am and 12:30pm. That makes the customers happy. If you deliver only about 68% of your pizzas within the time frame, you are at two sigma performance level. If you deliver on time 93% of the time, you are at 3 sigma. Pretty good, but you will still make a lot of customers very unhappy and you may go bankrupt in a competitive market. If you get 99.4% to the customer you are operating at 4 sigma. To get to six sigma you should deliver 99.9997% of the pizzas on time. Seeking six sigma is seeking the best of the best.