Problem 4. (20 points) A router is used to cut locating notches on a printed circuit board. The vibration level at the surface of the board as it is cut is considered to be a major source of dimensional variation in the notches. Two factors are thought to influence vibration: bit size (A) and cutting speed (B). Two bit sizes to and fin.) and two speeds (40 and 90 rpm) are selected, and four boards are cut at each set of conditions shown below. The response variable is vibration measured as the resultant vector of three accelerometers (x, y, and z) on each test circuit board. -- Treatment Replicate AB Combination I II III IV (1) 18.2 18.9 12.9 14.4 27.2 24.0 22.4 22.5 b 15.9 14.5 15.1 14.2 + + ab 41.0 43.9 36.3 39.9 + - a - + Consider the experiment described above. Analyze this experiment assuming that each one of the four replicates represents a block