Table 1.

Simulation results for estimates of IC50 and AUC and of Wald intervals and bootstrap intervals. Point and confidence limit estimates are computed as averages over the 1000 simulated data sets. The nominal level of coverage is 0.95. SE stands for standard error. Censoring rate is the proportion of 1000 estimated IC50s outside the concentration range.

	Case 1	Case 2	Case 3	Case 4
	IC50
True	1.49	15.69	37.76	43.88
Bias	0	0.09	0.59	−0.69
Asymptotic SE	0.10	2.51	6.03	7.42
Empirical SE	0.11	2.49	5.88	5.89
Censoring rate	0	0	0.065	0.264
Wald interval
Endpoints	(1.29, 1.69)	(10.89, 20.69)	(25.71, 49.37)	(26.22, 55.29)
Coverage	0.910	0.936	0.921	0.882
Bootstrap interval
Endpoints	(1.32, 1.69)	(11.91,21.66)	(29.69, 47.18)	(31.77, 49.20)
Coverage	0.901	0.909	0.926	0.940
	AUC
True	0.667	0.374	0.275	0.276
Bias	−0.001	0.000	0.000	0.000
Asymptotic SE	0.012	0.013	0.013	0.013
Empirical SE	0.013	0.013	0.013	0.013
Wald interval
Endpoints	(0.642, 0.690)	(0.349, 0.399)	(0.250, 0.300)	(0.251, 0.301)
Coverage	0.931	0.930	0.931	0.931
Bootstrap interval
Endpoints	(0.644, 0.688)	(0.352, 0.397)	(0.252, 0.298)	(0.254, 0.299)
Coverage	0.904	0.911	0.911	0.911