This paper establishes a criterion that measures approximately the average net income of a process under surveillance of an X̄ chart when the process is subject to random shifts in the process mean.

Control chart- a time-ordered plot of sample statistics, used to distinguish between random and nonrandom variability Control limits- the dividing lines between random and nonrandom deviations from ...

Often, however, “quality assurance” and “quality control” are used interchangeably, referring to the actions performed to ensure the quality of a product, service or process.

An Ishikawa diagram is a diagram that shows the causes of an event and is often used in manufacturing and product development.