TABLE 2.
Individual subject data showing the number of trials to reach criterion, the total number of visits, hit rate (H), false alarm rate (F), number of trials information (corresponding signal levels are indicated in Fig. 1), correlation between p(C)max and level, PFD asymptote, PFD slope, R2 of 3-line fit, and RT-versus-level slope
| Subject | No. trials to criterion, minimum possible? | No. visits | (Hlevel(1), Hlevel(2), . . .); F | Correlation between p(C)max and level in dB (r) | PFD asymptote p(C)max (95% lower confidence interval) (%) | PFD slope (%/dB re 1 μA) | PFD 3-Line fit (R2) | RT versus level slope [log (RT)/log (level in μA)] |
|---|---|---|---|---|---|---|---|---|
| s1 | 12, min | 4 | — | — | — | — | — | — |
| s2 | 63 | 2 | — | — | — | — | — | — |
| s3 | 12, min | 3 | (1/5, 0/6, 3/6, 3/6, 6/7, 4/4); 10/35 | 0.91* | 82.9 (69.3) | 6.3 | 0.77 | −0.78† |
| s4 | 14, min | 5 | (1/14, 0/15, 7/14, 9/14, 10/13); 8/68 | 0.90* | 83.2 (71.9) | 3.9 | 0.81 | N.S. |
| s5 | 18 | 3 | (–,‡ 0/22,‡ 1/4, 4/5, 7/7); 0/42 | 1.00* | 96.9 (89.7) | 30.6 | 1.00 | N.S. |
| (0/5, 1/6, 2/6, 6/7, 6/7); 3/28 | 0.98* | 87.6 (73.2) | 21.2 | 0.96 | N.S. | |||
| s6 | 12, min | 1 | — | — | — | — | — | — |
| s7 | Not met | 1 | — | — | — | — | — | — |
| s8 | 9, min | 2 | (1/7, 1/8, 7/7); 5/21 | 0.83* | 86.1 (70.1) | 8.0 | 0.90 | −0.34§ |
| (3/17, 13/18, 17/17); 11/53 | 0.90* | 91.2 (82.5) | 15.2 | 0.91 | −0.97† | |||
| s9 | 8, min | 1 | (10/18, 9/18, 22/22); 19/59 | 0.96* | 89.1 (79.6) | 2.1 | 0.86 | −0.28† |
| s10 | 26 | 1 | (0/13, 6/18, 16/18); 9/51 | 0.98* | 85.9 (76.2) | 6.0 | 0.83 | −0.61† |
| s11 | 24 | 2 | (9/13, 5/12, 11/14); 9/38 | 0.19¶ | 77.5 (64.2) | 0.1 | −0.29 | N.S. |
| s12 | 15 | 1 | (21/24); 17/72 | — | 82.5 (73.4) | — | — | — |
N.S. p > 0.4.
p < 0.000001 for a positive relationship.
p < 0.01 for a negative relationship.
The lower four of the five levels initially presented resulted in no hits; levels were subsequently raised until the PFD was bracketed. For analyses, all lower levels where H was zero were pooled at the highest of such levels. Pooling decreased the positive skew in p(C)max resulting from the conversion specified in the Materials and Methods section when H and F both equal zero and Nns far exceeds Ns. A reasonable estimate of p(C)max of 55% resulted (cf., Fig. 1). Otherwise, p(C)max >69%, and performance was statistically on the slope at these levels.
p = 0.10 for a negative relationship.
p > 0.125 for a positive relationship.