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4. A metal alloy is used to make components for aircraft engines. Cracking is a potentially serious problem in the final part, as it can lead to a non-recoverable failure. The objective of the experiment was to identify the key factors and possibly their interactions which have effects on cracks. Four factors were considered: pouring temperature (A), titanium content (B), heat temperature method (C), and the amount of grain refiner used (D). A full factorial experiment was conducted and the response of interest was the length of crack (in mmx 10-2). Each trial condition was replicated twice. The data are given in the Table below. Calculate the factorial effects, including main effects, two-way, three-way and four-way interaction effects. Which factorial effects are significant for the crack length? Run A B C D Crack length -1 6.48 5.87 -1 13.53 14.00 W N -L -1 -1 10.71 11.12 - - A -1 -1 15.89 16.39 9.57 9.34 4.02 3.77 -L 8.61 8.52 -1 12.37 11.89 - 7.88 8.24 -1 15.52 15.69 12.77 12.57 - - 18.24 18.07 13 - 10.90 11.35 14 -1 5.64 5.43 - - 15 10.30 10.06 16 -1 14.40 13.85