. A process engineer is trying to improve the life of a cutting tool. He has run a 23 experiment using cutting speed (A), metal hardness (B), and cutting angle (C) as the factors. The data from two replicates are shown here.

(a) Do any of the three factors affect tool life?

(b) What combination of factor levels produces the longest tool life?

(c) Is there a combination of cutting speed and cutting angle that always gives good results regardless of metal hardness?

Replicate Run I II a b ab be Z (1) 221 311 325 435 354 348 552 472 440 453 406 377 605 500 abc 392 419