Development of New Robust Optimal Score Function for the Weibull Distributed Error Term in Multilevel Models

Table 7

Bias and MSE of using Weibull, Wilcoxon, and REML methods when  = 3..

		REML		Weibull		Wilcoxon		Precision
N2	N1	Bias	MSE	Bias	MSE	Bias	MSE	Weib/REML	Weib/Wil	Wil/REML
5	5	2.152	2.39	0.242	0.307	2.219	2.715	1.121	0.987	1.136
	10	2.15	3.563	0.223	0.382	2.22	3.913	1.058	0.964	1.098
	20	2.126	5.767	0.236	0.71	2.201	6.23	1.028	0.952	1.08
	40	2.153	10.597	0.228	1.223	2.225	11.452	1.01	0.935	1.081
10	5	2.274	1.995	0.103	0.145	2.324	2.1	1.044	0.991	1.053
	10	2.27	2.626	0.095	0.166	2.314	2.761	1.041	0.99	1.051
	20	2.259	3.901	0.117	0.261	2.307	4.068	1.034	0.992	1.043
	40	2.274	6.548	0.105	0.402	2.318	6.852	1.029	0.983	1.046
20	5	2.317	1.717	0.04	0.107	2.344	1.765	1.027	0.999	1.028
	10	2.323	2.048	0.039	0.115	2.347	2.109	1.023	0.993	1.03
	20	2.323	2.731	0.036	0.146	2.348	2.804	1.022	0.995	1.027
	40	2.325	4.113	0.042	0.231	2.354	4.211	1.014	0.991	1.024
40	5	2.353	1.574	0.02	0.093	2.367	1.601	1.016	0.999	1.017
	10	2.349	1.743	0.035	0.099	2.364	1.767	1.013	0.999	1.014
	20	2.352	2.097	0.017	0.111	2.369	2.125	1.011	0.998	1.013
	40	2.346	2.787	0.034	0.136	2.36	2.828	1.012	0.998	1.015