Statistic^{b} | Observed mean (95% CI) | Null mean (95% CI) | P value |
---|---|---|---|

Association index | 2.4 (1.5–3.2) | 2.3 (1.9–2.7) | 0.58 |

Parsimony score | 16.1 (14–18) | 15.9 (13.8–17.7) | 0.52 |

Monophyletic clade size | |||

Gray squirrel | 2.3 (1–3) | 2.5 (2–4) | 0.95 |

Tick | 6.6 (6–8) | 4 (2.9–6.2) | 0.09 |

↵a See the maximum-likelihood tree shown in Fig. 2.

↵b The tests used three test statistics described previously (52). All three test statistics test the null hypothesis that the sampled species are distributed randomly among tip nodes. Association index, a measure of imbalance of internal nodes; parsimony score, the number of state changes in phylogeny; monophyletic clade size, a measure of the size of the clade sharing the same trait at the tips.