pic_stat_svar: Relationship between contrasts and their variances

In mwpennell/arbutus: Evaluate the adequacy of continuous trait models

Relationship between contrasts and their variances

Description

Fits a linear model between the absolute value of constrasts and their expected variances

Usage

pic_stat_svar(unit.tree)

Arguments

unit.tree

a unit.tree object

Details

This test statistic estimates the slope from fitting a linear model between the contrasts and their expected variance. It is used to evaluate whether the model is adequately capturing variation relative to branch lengths. If the model is adequate, we expect there not to be a relationship between the contrasts and their variances (i.e. slope ~ 0).

The slope of the contrasts and their variances is included as a default test statistic in the function calculate_pic_stat

The test statistic computed from a single unit.tree can be visualized with the function pic_stat_svar_plot.

Value

s.var the estimated slope paramter

See Also

calculate_pic_stat, default_pic_stat, pic_stat_svar_plot, lm

Examples

data(finch)
phy <- finch$phy
dat <- finch$data[,"wingL"]
unit.tree <- make_unit_tree(phy, data=dat)

## estimate slope
pic_stat_svar(unit.tree)

## visualization
pic_stat_svar_plot(unit.tree)

mwpennell/arbutus documentation built on Oct. 6, 2022, 10 a.m.