Six Sigma (6σ) is the way of doing things, a study of methods that consists of structured, disciplined, data driven analysis in order to eliminate defects. Six Sigma consists of set of tools and techniques to improve an existing process, product or service or to create a new robust one.
This was first introduced by engineer Bill Smith while working at Motorola in 1986. He used a statistical approach to problem solving using basic statistics methods and tools.
What does the sigma (σ) in six sigma stand for. Sigma or otherwise known as standard deviation is a statistical term. It is a measure of variation from the mean or average value in a classic bell distribution as shown below.
We now define mean or mu (μ) as shown above as the measure of central tendency in the given distribution. In order to find we do a sum of all the data points and then divide them by the number of data points, this gives us the mean of that data set.