Table 3.

Means and standard deviations for auditory P3a latencies (ms) and amplitudes (μV) at midlines by age-group (years).

		4–5 years (N = 40)				6–7 years (N = 82)				8–9 years (N = 46)				10–12 years (N = 10)
		Amplitude		Latency		Amplitude		Latency		Amplitude		Latency		Amplitude		Latency
		Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Fz	Infrequent	−4.05	6.0	321.5	35.6	−2.44	6.1	314.5	28.8	−0.31	7.0	320.1	31.3	−0.32	7.3	332.6	33.3
	Novel	3.18	9.8	318.0	30.2	7.38	9.3	319.1	31.6	6.81	9.4	329.0	31.4	12.76	5.8	337.2	24.1
	Frequent	2.58	6.4	320.6	24.5	−0.77	5.6	316.1	30.5	−1.17	6.0	317.4	37.6	−1.96	5.1	326.2	25.5
FCz	Infrequent	−0.92	6.7	331.5	32.1	0.16	6.0	314.4	27.2	1.54	6.9	316.7	28.8	2.61	6.4	312.8	35.1
	Novel	8.21	8.9	317.3	29.1	11.74	8.7	315.6	29.0	10.06	8.8	323.4	27.9	16.97	6.2	321.8	29.2
	Frequent	2.23	6.0	321.2	25.5	−0.84	5.3	322.1	29.9	−0.35	5.8	320.4	32.3	−2.34	4.4	332.6	25.9
Cz	Infrequent	−1.26	6.4	326.4	35.2	0.37	5.4	310.8	27.6	1.12	5.0	313.9	28.9	2.22	5.8	300.6	26.4
	Novel	6.15	8.9	311.2	29.5	10.33	7.9	309.5	30.0	7.55	7.8	325.8	30.1	15.70	5.0	323.0	23.7
	Frequent	1.07	6.2	321.1	28.4	−1.11	5.3	321.3	27.7	−0.18	5.4	324.0	33.5	−2.29	4.3	322.6	35.6
Pz	Infrequent	−1.77	5.5	331.5	39.1	0.38	4.7	314.7	41.0	0.82	5.0	317.2	33.5	1.10	2.9	318.8	36.6
	Novel	1.76	5.5	326.7	36.0	5.30	6.4	332.4	29.4	5.19	6.6	343.1	22.0	10.91	6.1	329.4	25.3
	Frequent	0.68	5.1	321.1	31.4	−0.78	4.0	316.8	35.6	0.51	3.9	329.2	37.0	−1.43	4.1	309.2	38.5