Question

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

	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

Produce the following for each problem:

• Residuals table
• Table to produce a Normal Probability Plot
• Normal probability plot in Normal paper
• Conclusion about Normal probability plot
• Residuals vs. Fitted values plot
• Residuals vs. Factor plot (for each factor)
• Conclusions after each plot
• Final conclusion about the adequacy of the model

Use MiniTab to produce the plots and models

Answer 1

Data input in MINITAB.

Two way ANOVA

Stat >> ANOVA >> Two way >>

Select Responce, Row Factor ( control factor ), and column factor ( uncontrollable factor )

Selct Garph

Selct residual lpt ( four in one )

Select ' Feed rate ' and ' depth of cut' for residual

Result ( output of minitab )

Graphs ( residual analysis results )

( Residual vs factor )