Table 3. Group comparison data from Fig. 3A—statistics.

Statistics for the group comparison data in Fig. 3A. Means and standard deviations (‘s.d.’) are given for the distributions with each nominal mean value between 5 and 12 (left column), for the randomly-generated starting distributions of real thresholds, and for the estimated thresholds from 2-down, 1-up (1 dB) staircases with 10, 20, and 100 reversals. Also shown for each set of distributions are the required numbers of cases (‘req. n’) for a statistically significant group difference when compared with the first distribution (centred on 5), based on a two-sample t-test with alpha level of 0.05 and 80% power.

Nominal  mean value	Starting distributions			Staircase: 10 reversals			Staircase: 20 reversals			Staircase: 100 reversals
	mean	s.d.	req. n	mean	s.d.	req. n	mean	s.d.	req. n	mean	s.d.	req. n
5	4.97	0.99	.	8.51	2.86	.	7.02	2.23	.	5.28	1.38	.
5.5	5.48	1.12	38	9.18	3.10	160	7.73	2.57	94	5.81	1.55	64
6	6.00	1.24	14	10.16	3.60	35	8.63	2.78	24	6.34	1.66	21
7	6.94	1.46	8	11.64	4.15	15	9.87	3.41	13	7.38	1.98	10
8	8.01	1.56	6	13.58	4.60	9	11.37	3.48	8	8.49	2.18	7
9	8.99	1.91	6	14.95	5.12	8	12.75	4.16	7	9.52	2.61	7
10	10.02	1.98	5	16.58	5.70	7	14.28	4.58	7	10.67	2.67	6
12	11.92	2.25	5	20.41	6.92	6	17.17	5.34	6	12.64	3.20	6