25. A researcher is interested in comparing the breaking strength of different laminated beams made from 3 different types of glue and 3 varieties of wood. To make the comparison, 5 beams of each of the 9 combinations were manufactured and then put under a stress test. The following table indicates the pressure readings at which each of the beams broke.

(a) Test the hypothesis that the wood and glue effect is additive.

(b) Test the hypothesis that the wood used does not affect the breaking strength.

(c) Test the hypothesis that the glue used does not affect the breaking strength.

Transcribed Image Text:

Wood Glue G1 G2 G3 196 208 214 216 258 250 WI 247 216 235 240 264 248 221 252 272 216 228 215 217 246 247 W2 240 224 235 219 261 250 236 241 255 230 242 212 218 255 251 W3 232 244 216 224 261 258 228 222 247