
170 Industrial control systems
Final equation in terms of uncoded variables:
Roughness 31 5 25 Webspeed 9 Vol tage 1 85
Webgap
×
. . . .00 0 0 0 00 0
−− × × + ×
× + ×
0 0 0 0 0
0 0 0
. .
.
25 Webspeed Voltage 4 Websp e e d
Webgap 5 Voltagge Webgap 1 Webspeed
Voltage Webg ap
× − ×
× ×
0 00.
Complete analysis of the example indicates that high Webspeed, low voltage,
and high webgap can be used to minimize surface roughness.
Table 6.8 Experimental Results for Plating Example Part (c)
Variable
Coefficient
estimate df Standard error
t for H0
coefficient = 0 Prob > |t|
Intercept 24.750 1 0.456
A −5.750 1 0.456 −12.60 0.0011
B 2.750 1 0.456 6.025 0.0092
C −1.500