For several years, a fully-automated plastic drinking cup production line used excessive amounts of raw materials (plastic PET pellets) due to a wide distribution in the weight of the formed cups. When process operators and engineers had tried to reduce the plastic pellet usage by reducing the average formed cup weight, many cups – because of the wide variation – fell below the customer-specified minimum weight. The process thus had to be reset to a higher weight target in order to avoid those out-of-specification cups. A previous process improvement team attempted to find the sources of variation through some data collection and a couple of two-factor/two-level full-factorial experiments. They were unsuccessful, however, as the factors used in the experiments did not explain the response variation.