7. A process engineer is trying to improve the life of a cutting tool. He has run a 23 experiment using cutting speed (A) [23-40 MPM], metal hardness (B) (90-95), and cutting angle (C) [45-90 degrees]. Replicate II 311 435 Run 1 a b ah c ac he abc 221 325 354 552 440 406 605 392 348 472 453 377 500 419 a Analyse and draw conclusions at a=0.05 b. What is the optimal level setting for the process with respect to the given levels for each factors? c. Develop a regression model that could derive exact optimal level setting.