Question

Two Ways ANOVA

An engineer suspects that the surface finish of a metal part is influenced by the feed rate and the depth of cut. She selects three feed rates and four depths of cut. She then conducts a factorial experiment and obtains the following data: (Use Minitab)

		Depth of	Cut (in)
Feed Rate (in/min)	0.15	0.18	0.20	0.25
	74	79	82	99
0.20	64	68	88	104
	60	73	92	96
	92	98	99	104
0.25	86	104	108	110
	88	88	95	99
	99	104	108	114
0.30	98	99	110	111
	102	95	99	107

1. Analyze the data and draw conclusions. Use a = 0.05.
2. Prepare appropriate residual plots and comment on the model’s adequacy.
3. Obtain point estimates of the mean surface finish at each feed rate.

Answer 1