std.paleoTS {paleoTS} | R Documentation |
Convert time-series to standard deviation units
Description
Convert time-series to standard deviation units
Usage
std.paleoTS(y, center = c("mean", "start"))
Arguments
y |
a |
center |
optional translation of time-series according to "mean" or "start"; see Details |
Details
The standardization expresses each sample mean as the deviation
from the overall mean, divided by the pooled within-sample standard deviation. Sample
variances are also divided by the pooled sample variance.
Essentially,
this converts paleontological time-series data into standard deviation
units, similar to the computation of evolutionary rates in haldanes. This
operation does not change the relative fit of models, but it does
facilitate the comparison of parameter estimates across time-series of
traits measured in different units.
If argument center
= "start"
the time-series is translated such that the trait mean of the first sample
is zero.
Value
the converted paleoTS
object
Examples
x <- sim.Stasis(ns = 8, theta = 1, omega = 4, vp = 2)
xs <- std.paleoTS(x, center = "start")
plot(x, ylim = range(c(x$mm, xs$mm)))
plot(xs, col = "red", add = TRUE)
legend(x = "topright", c("unstandardized", "standardized"), lty=1, col=c("black", "red"), cex=0.7)