Page 270 - Six Sigma Advanced Tools for Black Belts and Master Black Belts
P. 270
OTE/SPH
OTE/SPH
3:5
Char Count= 0
August 31, 2006
JWBK119-16
Robust Design 255
Table 16.12 Effect of replicates on confounding.
Number of replicates
Source Degrees of freedom r = 1 r = 2 r = 3 r = 4
Main effects k 3 3 3 3
Two-way interactions 1 / 2 k(k−1) 3 3 3 3
Error ν e 1 9 17 25
k
Total r (2 −1) 7 15 23 31
main effects and two-way interactions. Otherwise, four replicates would be preferred
since three replicates would result in confounding between the blocks and the two-
way interactions.
