Hello,
Some colleagues and I are running some phylogenetic ANOVAS using the geiger
package. In some of the analyses we get the same phylogentic p-value (very
small p-value) even though the F-statistic differs between the two analyses,
albeit it being relatively high in both instances. We were wondering why this
arises, to get better grip on how the analysis works. We thought it may have to
do with the randomizations to calculate the phylogenetic p-value. Or that the
F-statistics are quite high...
Below are two examples :
m11<-phy.anova(tree1,tmax,biozone,data.names=X,nsim=1000)
Standard ANOVA:
Analysis of Variance Table
Response: td$data
Df Sum Sq Mean Sq F value Pr(>F)
group 1 967.96 967.96 155.88 3.057e-12 ***
Residuals 25 155.24 6.21
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Phylogenetic p-value: 0.000999001
m12<-phy.anova(tree1,wt,biozone,data.names=X,nsim=1000)
Standard ANOVA:
Analysis of Variance Table
Response: td$data
Df Sum Sq Mean Sq F value Pr(>F)
group 1 602.88 602.88 109.01 1.333e-10 ***
Residuals 25 138.26 5.53
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Phylogenetic p-value: 0.000999001
Cheers,
Alejandro
__________________________________
Alejandro Gonzalez Voyer
Post-doc
NEW ADDRESS & NEW E-MAIL
Estación Biológica de Doñana (CSIC)
Avenida Américo Vespucio s/n
41092 Sevilla
Spain
E-mail: alejandro.gonza...@ebd.csic.es
Tel: +34- 954 466700, ext 1749
Website (From my previous position):
http://www.iee.uu.se/zooekol/default.php?type=personalpage&lang=en&id=146
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