Table 2.

n = 50.

Parameters	True value	Estimated value	Root mean square	Deviation
β 0	0.5	0.540	0.032	0.040
β 1	0.7	0.680	0.042	0.020
β 2	0.7	0.730	0.039	0.030
β 3	0.7	0.670	0.042	0.030
β 4	0.7	0.722	0.040	0.022
σ u	0.8	0.860	0.086	0.060