This section discusses the vital concepts of variation and accuracy, and how they relate to a manufacturing process. This excerpt shows how the book uses extensive figures to teach these concepts, and prepares students to understand and use control charts in a manufacturing operation. Two factors define a manufacturing process' ability to meet specifications. A manufacturing operation's goal is to make product that meets the customer's needs.
Specifications reflect the customer's needs.
Product that is in specification is good, and we can sell it to the customer. Product that is out of specification is bad, and the customer will not accept it. We must rework it, or scrap it. Two factors affect the process' performance. It is easy to explain these by treating the specification as a target for a gun.