Table 16.

$S/N$ ratios of the gray relational grade.

Level	A	B	C	D	E	F	G
1	−4.68	−5.42	−4.65	−6.73	−5.79	−5.20	−5.49
2	−5.02	−5.54	−5.73	−5.61	−5.38	−5.33	−5.16
3	−4.44	−5.40	−5.98	−4.02	−5.20	−5.83	−5.71
4	−6.01
5	−6.80
6	−5.77
$Delta$	1.91	0.14	1.32	2.71	0.59	0.62	0.55
$Rank$	2	7	3	1	5	4	6