fit3models {paleoTS} | R Documentation |
Function fits three models to an evolutionary time series: (1) general random walk, (2) unbiased random walk, and (3) stasis.
fit3models(y, pool = TRUE, silent = FALSE, wts = "AICc")
y |
a paleoTS object |
pool |
logical, if TRUE, variances are pooled across samples |
silent |
logical, if TRUE, results are not printed |
wts |
what version of AIC to use for calculation of Akaike weights; either AIC or AICc |
If silent=FALSE
, function fit3models
returns a vector of parameter estimates; if silent=TRUE
, a list with the following components is returned, with models listed in the order of general random walk, unbiased random walk, and stasis:
aic |
Akaike information criterion |
aicc |
AIC modified for low sample sizes |
logl |
log-likelihoods of the three models |
hats |
parameter estimates for general random walk (mstep, vstep), unbiased random walk (vstep) and stasis (theta, omega) models |
ak.wts |
vector of Akaike weights |
Gene Hunt
Hunt, G. 2006. Fitting and comparing models of phyletic evolution: random walks and beyond. Paleobiology32:578–601.
y<- sim.GRW(ns=30, ms=0.5, vs=0.2) fit3models(y) y<- sim.Stasis(ns=30, theta=0, omega=0) fit3models(y)