Table 6.

Estimated type I error rates and power for detecting differences resulting from differing average numbers of FP marks (λ) for AUC=0.8 under a simulation model based on normal distributions with a sample size of 100 subjects and 1000 simulations. The symbols in the table heading are the following simulation parameters: AUC - is the degree of separation between the distribution of FP and TP ratings; b - is the ratio of the standard deviation of FP ratings to that of TP ratings; λ - is the average number of FP marks per subject; ν - is the average proportion of the marked lesions; t - is the number of lesions on an actually positive subject.

Type I error rate
			λ=0.5			λ=1.0			λ=2.0
			θ	A1	A2	θ	A1	A2	θ	A1	A2
1∕b	t	υ
1	1	0.5	0.049	0.048	0.046	0.066	0.066	0.065	0.056	0.053	0.056
		0.9	0.056	0.054	0.056	0.046	0.044	0.037	0.057	0.057	0.052
	3	0.5	0.049	0.055	0.061	0.062	0.051	0.052	0.048	0.039	0.038
		0.9	0.029	0.051	0.052	0.045	0.040	0.034	0.052	0.056	0.051
2	1	0.5	0.060	0.053	0.054	0.061	0.055	0.056	0.055	0.046	0.051
		0.9	0.048	0.053	0.046	0.058	0.062	0.066	0.049	0.053	0.054
	3	0.5	0.058	0.040	0.044	0.057	0.053	0.049	0.054	0.064	0.055
		0.9	0.039	0.045	0.049	0.055	0.065	0.063	0.051	0.047	0.041
Statistical power
			λ=1.0 versus λ=0.5			λ=2.0 versus λ=0.5			λ=2.0 versus λ=1.0
			θ	A1	A2	θ	A1	A2	θ	A1	A2
1∕b	t	υ
1	1	0.5	0.090	0.114	0.132	0.207	0.376	0.431	0.101	0.136	0.153
		0.9	0.268	0.411	0.512	0.805	0.945	0.973	0.312	0.457	0.547
	3	0.5	0.160	0.255	0.314	0.582	0.818	0.878	0.234	0.348	0.378
		0.9	0.234	0.333	0.401	0.783	0.859	0.914	0.312	0.310	0.368
2	1	0.5	0.071	0.087	0.129	0.125	0.302	0.462	0.076	0.121	0.162
		0.9	0.178	0.315	0.488	0.569	0.880	0.976	0.166	0.367	0.541
	3	0.5	0.093	0.219	0.345	0.295	0.725	0.916	0.132	0.282	0.407
		0.9	0.128	0.328	0.486	0.462	0.811	0.961	0.141	0.265	0.428