. 1997 Dec 9;94(25):14190–14194. doi: 10.1073/pnas.94.25.14190

Table 1.

ROC parameters for yn and 2afc trials sorted by subject and contrast

Subject	Contrast	Task	Trials	A	s_A	B	s_B	P(B)	d_a	sd_a	Z	P(Z)
G.Y. (hemianope)	0.95	yn	250	1.570	0.203	1.300	0.176	NS	1.354	0.146	3.729	^***
		2afc	250	2.623	0.389	0.450	0.179	NS	2.392	0.237
	0.85	yn	250	1.247	0.158	0.927	0.117	NS	1.293	0.144	3.092	^***
		2afc	250	2.570	0.324	0.896	0.191	NS	1.914	0.140
	0.75	yn	250	0.947	0.152	1.086	0.130	NS	0.908	0.137	4.707	^***
		2afc	250	2.401	0.286	0.872	0.175	NS	1.810	0.134
	0.65	yn	250	0.855	0.146	1.052	0.124	NS	0.833	0.137	4.287	^***
		2afc	250	2.203	0.254	0.909	0.165	NS	1.631	0.126
M.F. (control)	0.014	yn	250	1.581	0.211	1.356	0.184	NS	1.327	0.147	−1.024	NS
		2afc	250	1.568	0.185	0.947	0.130	NS	1.139	0.110
	0.011	yn	250	1.713	0.244	1.600	0.226	^***	1.285	0.148	0.154	NS
		2afc	250	1.843	0.215	0.982	0.154	NS	1.314	0.117
	0.008	yn	250	1.916	0.271	1.701	0.256	^***	1.373	0.152	0.308	NS
		2afc	250	1.541	0.185	0.994	0.134	NS	1.093	0.109
	0.005	yn	250	2.077	0.308	1.883	0.288	^***	1.378	0.153	−1.260	NS
		2afc	250	1.500	0.172	0.856	0.117	NS	1.140	0.110
S.R. (control)	0.011	yn	250	2.493	0.327	1.157	0.218	NS	2.306	0.191	0.228	NS
		2afc	250	3.177	0.609	0.896	0.315	NS	2.367	0.187
	0.010	yn	250	3.208	0.481	1.818	0.349	NS	2.187	0.187	−0.004	NS
		2afc	250	2.991	0.491	0.934	0.277	NS	2.186	0.165
	0.009	yn	250	−0.074	0.147	1.111	0.135	NS	−0.069	0.138	0.308	NS
		2afc	250	0.273	0.174	1.277	0.172	NS	0.168	0.106
	0.008	yn	250	0.247	0.143	1.072	0.124	NS	0.238	0.137	−1.260	NS
		2afc	250	0.423	0.156	1.024	0.126	NS	0.295	0.105
P.A. (control)	0.020	yn	250	5.349	–	1.895	–	–	3.53	–	–	–
		2afc	250	2.350	–	0.065	–	–	1.82	–
	0.015	yn	250	7.861	–	1.100	–	–	7.479	–	–	–
		2afc	250	3.313	–	0.895	–	–	1.868
	0.010	yn	250	0.909	0.155	1.155	0.139	NS	0.842	0.137	1.912	^*
		2afc	250	1.612	0.197	0.924	0.143	NS	1.184	0.115
	0.005	yn	250	1.154	0.177	1.292	0.168	NS	0.999	0.141	0.045	NS
		2afc	250	1.288	0.159	0.797	0.111	NS	1.007	0.109

A, y intercept of ROC plotted in z coordinates, equal to d′ when variances of the two underlying distributions are equal; s_A, SD of A; B, slope of ROC plotted in z coordinates, equivalent to the ratio of the variances of the two underlying distributions; s_B, SD of B; P(B), probability of B deviating from a value of 1.0 by chance; d_a, sensitivity index, assuming unequal variance of underlying distributions; sd_a, SD of d_a; Z, difference between d_a(yn) and d_a(2afc) expressed as a normal deviate (see ref. 30); and P, probability of the difference between d_a(yn) and d_a(2afc) arising by chance (∗, P < 0.05; ∗∗, P < 0.01; ∗∗∗, P < 0.001). Parameters are presented only if ROCs could be fitted adequately at the P < 0.01 level.