The rework time required for a machine was found to depend on the speed at which the machine was run (A), the lubricant used while working (B), and the hardness of the metal used in the machine (C). Two levels of each factor were chosen and a single replicate of a 2³experiment was run. The rework time data (in hours) are shown in the following table.

(a) These treatments cannot all be run under the same conditions. Set up a design to run these observations in two blocks of four

observations each, with ABC confounded with blocks.

(b) Analyze the data.

Treatment Combination Time (in hours) (1) 27 34 38 ab 59 44 40 ac bc 63 abc 37