This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.MathematicsWikipedia:WikiProject MathematicsTemplate:WikiProject Mathematicsmathematics
There is no point in listing an equation if you are not going to define what the variables mean. Namely, what on earth is do USL and LSL stand for? Even sigma should be defined for those who do not know what they are looking at.