14.42 A control valve needs to be very sensitive to the input voltage, thus generating a good output voltage.

An engineer turns the control bolts to change the input voltage. The book SN-Ratio for the Quality Evaluation, published by the Japanese Standards Association

(1988), described a study on how these three factors (relative position of control bolts, control range of bolts, and input voltage) affect the sensitivity of a control valve. The factors and their levels are shown below. The data show the sensitivity of a control valve.

Factor A, relative position of control bolts:
center −0.5, center, and center +0.5 Factor B, control range of bolts:
2, 4.5, and 7 (mm)
Factor C, input voltage:
100, 120, and 150 (V)
C A B C1 C2 C3 A1 B1 151 135 151 135 151 138 A1 B2 178 171 180 173 181 174 A1 B3 204 190 205 190 206 192 A2 B1 156 148 158 149 158 150 A2 B2 183 168 183 170 183 172 A2 B3 210 204 211 203 213 204 A3 B1 161 145 162 148 163 148 A3 B2 189 182 191 184 192 183 A3 B3 215 202 216 203 217 205 Perform an analysis of variance with α = 0.05 to test for significant main and interaction effects. Draw conclusions.