An article in Quality Progress (For Starbucks, Its in the Bag, March 2011, pp. 18-23) describes using a central composite design to improve the packaging

An article in Quality Progress (€œFor Starbucks, It€™s in the Bag€, March 2011, pp. 18-23) describes using a central composite design to improve the packaging of one-pound coffee. The objective is to produce an airtight seal that is easy to open without damaging the top of the coffee bag. The experimenters studied three factors €“ x1 = plastic viscosity (300-400 centipoise), x2 = clamp pressure (170-190 psi), and x3 = plate gap (-3, +3 mm) €“ and two responses, y1 = tear and y2 = leakage. The design is shown in Table 14E.8.

TABLE 14E.8 The Coffee Bag Experiment in Exercise 14.15 Run Viscosity Pressure Plate Gap Tear Leakage Center Axial 350170 0 Factorial 319 Factorial 380 74 180.85 0.05 Center 350 180 0 0 0.15 05 186 18 0.45 0.15 350 300 180 180 180 0 0 0 0 0 0.35 0.15 0.3 0.45 0.7 0.25 1.9 0 025 0.05 Axial 350 190 Center 350 Factorial 319 Factorial 380 Axial Factorial 380 Center 350 180 186 18 0.1 0.35 186 1.8 180 174-18 180 180 -3 174 18 0.05 02 174 186 180 0.15 0.4 3.9 0 350 0.45 0.55 02 0 350 Factorial 319 Factorial 319 Factorial 380 Center 350 1.8 0.4 025 18 43 005