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 Run I II (1) 221 311 a 325 435 b 354 348 ah 552 472 440 453 406 377 605 500 392 419 bc abc 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.