A router is needed to cut location notches on a printed circuit board (PCB). The cutting process creates vibration on the board and causes the dimensional variation of the notch position. An experimental study is conducted to identify the cause of vibration. Two factors, bit size (A) and cutting speed (B), are thought to influence the vibration. Two bit sizes (1/16 in and 1/8 in) and two speeds [40 rpm and 90 rpm (r/min)] are selected, and four boards are cut at each set of conditions shown in the next Table. The response variable is the vibration measured on each test circuit board.

Y [vibration (four replicates, n = 4) Run (cutting number (hit size) speed) 1 2 3 18.0 120 14.A - AUNH 27.2 2LO 22.4 925 + 16.0 15.1 410 363 30.0Run columns Responses Replicates Contrast umber Effects Total A B AB 2 3 4 A B AB -1 -1 1 1 -1 -1 W -1 1 -1 1 1 1 Summation Effect=Contrast/(2k-1*n) = YA+-YA Sum of square SS = Contrast2/(2* * n) B -381 =23.8313+8.31X,+3.77X,+4.36X, X, /16-23 B. =16.63/ B,=7.45 B 12 2=8.31 /2=3.77 1/2= 8313 6 Y= ! + (-1) + (+1) + (-1) * (+1) = 1