2. Reconsider the leaf spring experiment from the previous problem. Suppose that factors A, B and C are controllable variables, and that factors D and E are noise factors. Set up a crossed array design to investigate this problem, assuming that all of the two-factor interactions involving the controllable variables are thought to be important. What type of design have you obtained?

Reconsider the leaf spring experiment in Table Below. Suppose that the objective is to find a set of conditions where the mean free height is as close as possible to 7.6 inches with a variance of free height as small as possible. What conditions would you recommend to achieve these objectives? B D + - + + 1 + + 1 E() 7.78,7.78, 7.81 8.15, 8.18, 7.88 7.50, 7.56, 7.50 7.59, 7.56, 7.75 7.54, 8.00, 7.88 7.69, 8.09, 8.06 7.56, 7.52, 7.44 7.56, 7.81, 7.69 E(+) 7.50, 7,25, 7.12 7.88, 7.88, 7.44 7.50, 7.56, 7.50 7.63, 7.75, 7.56 7.32, 7.44, 7.44 7.56, 7.69, 7.62 7.18, 7.18, 7.25 7.81, 7.50, 7.59 j 7.54 7.90 7.52 7.64 7.60 7.79 7.36 7.66 52 0.090 0.071 0.001 0.008 0.074 0.053 0.030 0.017 + + 1 + + + +