Dear all, I'm trying to perform a PGLS with arbitrary branch lengths (I used branch lengths = 1). The tree is non-ultrametric. Here is a result with Pagel's Lambda: vf<-diag(vcv(tree)) fit<-gls(FCLrelative~LogBodymass,correlation=Pagel,data=DF,method="ML",weights=varFixed(-vf)) summary(fit) Model: FCLrelative ~ LogBodymass Data: DF AIC BIC logLik 42.28777 49.77257 -17.14388
Correlation Structure: corPagel Formula: ~1 Parameter estimate(s): lambda 1.039835 Variance function: Structure: fixed weights Formula: ~vf Coefficients: Value Std.Error t-value p-value (Intercept) -0.17662926 0.26166738 -0.6750144 0.5030 LogBodymass 0.05865737 0.05766171 1.0172672 0.3143 Correlation: (Intr) LogBodymass -0.651 Standardized residuals: Min Q1 Med Q3 Max -2.36346640 -0.21848447 0.08326376 0.46156642 1.15440168 Residual standard error: 0.2388999 Degrees of freedom: 48 total; 46 residual As you see my lambda is >1, what shouldn't happen. Is this normal when we set all branch lengths to an arbitrary value? Thank you very much in advance. Best regards, Sérgio. -- Com os melhores cumprimentos, Sérgio Ferreira Cardoso. -------------------- Best regards, Sérgio Ferreira Cardoso MSc. Paleontology candidate Departamento de Ciências da Terra - FCT /Universidade Nova de Lisboa Geociências - Universidade de Évora Lisboa, Portugal [[alternative HTML version deleted]] _______________________________________________ R-sig-phylo mailing list - R-sig-phylo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-phylo Searchable archive at http://www.mail-archive.com/r-sig-phylo@r-project.org/