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 in Table 13E.2. (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