Table 2.

Simulation results for selected parameters in the piece-wise linear trajectory model.

	true weights				estimated weights
	bias	V1	V2	coverage	bias	V1	V2	coverage
“independence” working correlation structure
n = 50
β 2	0.01	0.89	0.90	0.93	−0.01	0.89	0.87	0.97
β 4	0.00	0.13	0.14	0.93	0.01	0.15	0.13	0.97
β 6	−0.01	0.15	0.16	0.94	−0.01	0.16	0.15	0.96
β 7	0.01	0.05	0.06	0.93	0.01	0.07	0.06	0.96
n = 100
β 2	−0.03	0.47	0.46	0.95	−0.03	0.46	0.44	0.96
β 4	0.01	0.071	0.073	0.94	0.01	0.072	0.069	0.97
β 6	0.01	0.078	0.080	0.93	0.01	0.077	0.075	0.96
β 7	0.02	0.027	0.030	0.92	0.02	0.029	0.028	0.95
n = 300
β 2	−0.02	0.16	0.16	0.95	−0.02	0.16	0.15	0.96
β 4	0.00	0.024	0.024	0.95	−0.00	0.023	0.022	0.96
β 6	0.01	0.026	0.025	0.95	0.01	0.024	0.023	0.96
β 7	0.01	0.01	0.01	0.94	0.01	0.01	0.01	0.94
“true” working correlation structure
n = 50
β 2	−0.01	0.86	0.88	0.93	−0.01	0.87	0.84	0.97
β 4	0.00	0.12	0.13	0.92	0.01	0.13	0.12	0.96
β 6	0.01	0.14	0.15	0.92	0.01	0.15	0.14	0.97
β 7	0.00	0.05	0.06	0.91	0.00	0.06	0.06	0.93
n = 100
β 2	−0.03	0.45	0.45	0.95	−0.03	0.43	0.43	0.96
β 4	0.01	0.072	0.071	0.95	0.01	0.069	0.067	0.96
β 6	0.01	0.075	0.077	0.92	0.01	0.076	0.074	0.96
β 7	0.02	0.027	0.028	0.93	0.02	0.029	0.028	0.95
n = 300
β 2	−0.02	0.15	0.15	0.95	−0.02	0.14	0.14	0.96
β 4	−0.00	0.023	0.024	0.94	−0.00	0.024	0.023	0.96
β 6	0.01	0.025	0.026	0.93	0.01	0.025	0.024	0.96
β 7	0.01	0.01	0.01	0.94	0.01	0.01	0.01	0.94

V1: mean estimated variance; V2: empirical variance; coverage: empirical coverage rate for the 95% confidence interval.