Table 11.

Results of Student’s t-test and Cochran’s Q test for roughness parameters on the lateral face of the AZ31 magnesium alloy, λ_s = 20° tool.

λs = 20° Lateral Face of the AZ31
Student’s t-Test
Roughness Parameter	vc 400 vs. 1200					fz 0.05 vs. 0.3
	Mean	Mean	Test	df	P-Value	Mean	Mean	Test	df	p-Value
Ra	0.865	0.2802	18.87493	8	0	-	-	-	-	-
Rz	3.642	1.474	11.44865	8	0.000003	-	-	-	-	-
RSm	0.4284	0.228	10.31757	8	0.000007	0.1568	0.2928	-9.9378	8	0.000009
Rsk	0.5294	0.1632	1.69294	8	0.128923	0.2238	0.6018	-1.8519	8	0.101177
Rku	2.2722	2.8788	−2.46516	8	0.039004	2.9852	3.2926	-0.674	8	0.519308
Cochran’s Q test
Roughness parameter	vc 400 vs. 1200					fz 0.05 vs. 0.3
	Mean	Mean	Test *	df	p-Value	Mean	Mean	Test *	df	p-Value
Ra	-	-	-	-	-	0.2492	0.5136	−4.2146	4.955853	0.008535
Rz	-	-	-	-	-	1.31	2.542	−5.0265	4.892736	0.004262

* Test with independent variance estimation.