α 0.5 0.598 0.028 1.0 0.548 0.096 1.5 0.515 0.173 2.0 0.490 0.235 2.5 0.466 0.277 3.0 0.439 0.299

Table 1: Asymptotic Relative Efficience of the Estimators and .The study was conducted with ß2=0, k=2 groups m1= m2=20 individuals per group; The follow-up times are identical for the two groups.