Table 1.

Comparison between $\mathrm{Var}\left(\widehat{\mu }\right)$, the ${\widehat{S}}^2$ estimator defined in Gilbert et al. (2005), and our estimator S² for different sample size N. All quantities were calculated through 10,000 runs from the simulation described in Section 3. In the star topology, the branch lengths of the phylogenetic tree were distributed according to a Poisson of mean 10. The non-star topology consisted of two stars with Poisson distribution with means 10 and 5 connected by a branch of length 12.

	Star topology			Non-star topology
N	$\mathrm{Var}\left(\widehat{\mu }\right)$	${\widehat{S}}^2$	S 2	$\mathrm{Var}\left(\widehat{\mu }\right)$	${\widehat{S}}^2$	S 2
4	9.939	1.972	9.96	19.6995	6.9244	19.281
5	7.889	2.571	7.969	14.395	7.425	15.144
8	4.98	2.713	5.008	8.291	5.738	8.158
10	3.973	2.513	4.002	6.27	4.899	6.223
20	2.051	1.61	2.003	2.972	2.856	2.955
30	1.312	1.158	1.331	1.893	1.97	1.92
50	0.799	0.737	0.7998	1.135	1.215	1.13
100	0.399	0.384	0.3998	0.558	0.623	0.559