An article by L.B. Hare (“In the Soup: A Case Study to Identify Contributors to Filling Variability,” Journal of Quality Technology, vol. 20, pp. 36-43) describe a factorial experiment used to study the filling variability of dry soup mix packages. The factors are A = number of mixing ports through which the vegetable oil was added (1, 2), B = temperature surrounding the mixer (cooled, ambient), C = mixing time (60, 80 sec), D = batch weight (1,500, 2,000 lb), and E = number of days of delays between mixing and packaging (1, 7). Between 125 and 150 packages of soup were sampled over an eight-hour period for each run in the design, and the standard deviation of package weight was used as the response variable. The design and resulting data are shown in Table 13E.7.
(a) The generator is E = −ABCD, the alternate fraction.