Table 1.

Results from a single nested variance components' analysis model for amplitude and for phase with percentages of total variance from each variance component factor analyzed.

	Variance component	Parameter estimate	Standard error	Percentage of total variance (%)	P value
Amplitude (μV)	Subject	0.06	0.04	53.1	0.14
	Eye	0.01	0.007	8.8	0.05
	Operator	0.03	0.01	26.6	0.05
	Trial*Operator	0.005	0.003	4.4	0.09
	Unexplained variability	0.008	0.002	7.1	<0.001
Phase (π rad)	Subject	0.004	0.002	36.4	0.04
	Eye	0.0001	3.3E-5	9.1	0.12
	Operator	0.0002	0.0001	18.2	0.25
	Trial*Operator	0.0001	9.4E-5	9.1	0.19
	Unexplained variability	0.0003	6.9E-5	27.2	<0.001