Value-added Management with Design of Experiments

The story is told of a traveler in western Europe near the end of the Middle Ages, who came upon a vast construction project in a small town. As he drew near the site, the traveler saw stonecutters, masons, plumbers, carpenters and other craftsmen busily engaged in the construction of a huge edifice. He came upon three masons working side by side, and asked each of them what they were doing.