Skip to main content
. Author manuscript; available in PMC: 2011 Jun 1.
Published in final edited form as: J Evol Biol. 2010 Apr 6;23(6):1183–1194. doi: 10.1111/j.1420-9101.2010.01983.x

Table 4.

Sexual differences in hematocrit and RBC counts among 45 primate species. Results are based on paired t-tests conducted on species mean values. For hematocrit, the best fitting model included phylogeny but not error in the estimation of species means; however for RBC count the best fitting model included both phylogeny and error. Our results indicate that males have significantly higher hematocrit and RBC counts than females, regardless of model.

Trait & Comparison Test MLEs(λ, σε2); log(L) d̄ t df (N − p) P
Hematocrit M – F non-phylogenetic/non-error log(L) = 96.02 0.038 8.793 44 <0.0001
phylogenetic/non-error λ = 0.581; log(L) = 102.42 0.030 2.343 43 0.0238
phylogenetic/error λ = 0.581; σε2 = 0.0; log(L) = 102.42 0.030 2.316 42 0.0255
RBC M – F non-phylogenetic/non-error log(L) = −21.75 0.482 8.157 44 <0.0001
phylogenetic/non-error λ = 0.343; log(L) = −20.57 0.432 2.959 43 0.0050
phylogenetic/error λ = 0.964; σε2 = 8.20; log(L) = −19.21 0.360 4.431 42 <0.0001

Note: M = Males, F = Females