calib.t: Comparison dates calibrated using both the t distribution...
In rice: Radiocarbon Equations

calib.t

R Documentation

Comparison dates calibrated using both the t distribution (Christen and Perez 2009) and the normal distribution.

Description

Visualise how a date calibrates using the t distribution and the normal distribution.

Usage

calib.t(
  y = 2450,
  er = 50,
  t.a = 3,
  t.b = 4,
  cc = 1,
  postbomb = FALSE,
  glue = 0,
  deltaR = 0,
  deltaSTD = 0,
  as.F = FALSE,
  is.F = FALSE,
  BCAD = FALSE,
  zero = FALSE,
  cal.rev = TRUE,
  cc.dir = c(),
  normal.col = "red",
  normal.lwd = 1.5,
  t.col = rgb(0, 0, 0, 0.25),
  t.border = rgb(0, 0, 0, 0, 0.25),
  xlim = c(),
  ylim = c()
)

Arguments

`y`	The reported mean of the date.
`er`	The reported error of the date.
`t.a`	Value for the t parameter `a`.
`t.b`	Value for the t parameter `b`.
`cc`	calibration curve for the radiocarbon date(s) (see the `rintcal` package).
`postbomb`	Which postbomb curve to use for negative 14C dates.
`glue`	Glue postbomb and prebomb curves together. Defaults to 0 (none), can be 1 (IntCal20 + NH1), 2 (IntCal20 + NH2), 3 (IntCal20 + NH3), 4 (SHCal20 + SH1-2) or 5 (SHCal20 + SH3). Note that this will override the value of cc.
`deltaR`	Age offset (e.g. for marine samples).
`deltaSTD`	Uncertainty of the age offset (1 standard deviation).
`as.F`	Whether or not to calculate ages in the F14C timescale. Defaults to `as.F=FALSE`, which uses the C14 timescale.
`is.F`	Use this if the provided date is in the F14C timescale.
`BCAD`	Which calendar scale to use. Defaults to cal BP, `BCAD=FALSE`.
`zero`	Whether or not zero BC/AD should be included if using BCAD=TRUE. Defaults to `zero=FALSE`.
`cal.rev`	Reverse the calendar age axis. Defaults to TRUE
`cc.dir`	Directory where the calibration curves for C14 dates `cc` are allocated. By default `cc.dir=c()`. Use `cc.dir="."` to choose current working directory. Use `cc.dir="Curves/"` to choose sub-folder `Curves/`.
`normal.col`	Colour of the normal curve
`normal.lwd`	Line width of the normal curve
`t.col`	Colour of the t histogram
`t.border`	Colour of the border of the t histogram
`xlim`	x axis limits
`ylim`	y axis limits

Details

Radiocarbon and other dates are usually modelled using the normal distribution (red curve). The t approach (grey distribution) however allows for wider tails and thus tends to better accommodate outlying dates. This distribution requires two parameters, called 'a' and 'b'.