(Data file: lathe1) The data in the file lathe1 are the results of an experiment on characterizing the life of a drill bit in cutting steel on a lathe. Two factors were varied in the experiment, Speed...

(Data file: lathe1) The data in the file lathe1 are the results of an experiment on characterizing the life of a drill bit in cutting steel on a lathe. Two factors were varied in the experiment, Speed and Feed rate. The response is Life, the total time until the drill bit fails, in minutes. The values of Speed and Feed in the data have been coded by computing

The coded variables are centered at zero. Coding has no material effect on the analysis but can be convenient in interpreting coefficient estimates.