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phytools (version 0.5-38)

phyl.RMA: Phylogenetic reduced major axis (RMA) regression

Description

This function performs phylogenetic RMA regression.

Usage

phyl.RMA(x, y, tree, method="BM", lambda=NULL, fixed=FALSE, h0=1.0)

Arguments

x
vector with names.
y
vector with names.
tree
a phylogenetic tree in "phylo" format.
method
method to obtain the correlation structure: can be "BM" or "lambda".
lambda
value of lambda for fixed $\lambda$.
fixed
logical value indicating whether or not $\lambda$ should be optimized using likelihood.
h0
null hypothesis for beta. Defaults to 1.0. Note that a null hypothesis of 0.0 is not allowed.

Value

A list with the following components:
RMA.beta
a vector of RMA regression coefficients.
V
a VCV matrix for the traits.
lambda
fitted value of lambda (method="lambda" only).
logL
log-likelihood (method="lambda" only).
test
a vector containing results for hypothesis tests on beta.
resid
a vector of residuals for y given x.

Details

Optionally jointly estimates lambda if method="lambda". Likelihood optimization of lambda is performed using optimize on the interval (0,1). Note that some statistician think there is never a condition in which a reduced-major-axis regression should be used.

References

Revell, L. J. (2012) phytools: An R package for phylogenetic comparative biology (and other things). Methods Ecol. Evol., 3, 217-223.

See Also

phyl.cca, phyl.pca, phyl.resid