TABLE II.

Results from the three-way ANOVA conducted with the human-observer scores. The analysis tested acquisition strategy, observer and phantom density as factors. The protocol and density effects, as well as the interaction between them, were significant at the α = 0.05 level. The corresponding p-values are indicated in boldface.

Factor	df	ss	F	Pr(>F)
Protocol	6	0.012	6.32	4.3×10−4
Observer	2	0.0086	1.34	0.28
Density	2	7.58	1179.61	2.2×10−16
Protocol:observer	12	0.016	0.42	0.94
Protocol:density	12	0.10	2.58	0.023
Observer:density	4	0.0008	0.06	0.99
Residuals	24	0.077