dbED: Summarizing the distribution of a number of equivalent dose values

Description

Calculating statistical parameters (mean, standard deviation, skewness, kurtosis, over-dispersion); performing a homogeneity test; drawing a histogram and a probability density plot.

Usage

dbED(EDdata, aliquot=c("sa","sg"), plot = TRUE, from = NULL, 
     to = NULL, step = 0.1, nbin = 15, samplename = NULL)

Arguments

EDdata

data.frame(required): a number of equivalent doses and their standard errors (two columns)

aliquot

character(with default): single-aliquot ("sa") or single-grain ("sg"), default aliquot="sa"

plot

logical(with default): draw a histogram and a probability density plot or not

from

numeric(optional): the desired lower limit on x-axis

numeric(optional): the desired upper limit on x-axis

step

numeric(with default): a step size used for constructing the probability density plot. Finer step value gives smoother density curve

nbin

numeric(with default): the desired number of intervals in the histogram

samplename

character(optional): the name of the sample

Value

Return a list that contains following elements:
summaryEDa basically statistical summary about the given equvalent dose values
mlpEDthe mean of the lowest percent [x] of equivalent dose values (Olley et al, 1998)
homogeneitythe results of simple homogeneity test (Galbraith, 2003)
skewnessthe skewness of equivalent dose values (Bailey and Arnold, 2006)
kurtosisthe kurtosis of equivalent dose values (Bailey and Arnold, 2006)
proposala proposed statistical age model (Bailey and Arnold, 2006; Arnold et al, 2007) that depends on the type of aliquot ("sg" or "sa"), which cannot be relied on absolutely

References

Olley, J.M., Caitcheon, G., Murray, A.S., 1998. The distribution of apparent dose as determined by optically stimulated luminescence in small aliquots of fluvial quartz: implications for dating young sediments. Quaternary Geochronology, 17, pp.1033-1040.

Galbraith, R., 2003. A simple homogeneity test for estimates of dose obtained using OSL. Ancient TL, 21(2), pp.75-77.

Bailey, R.M., Arnold, L.J., 2006. Statistical modelling of single grain quartz De distributions and an assessment of procedures for estimating burial dose. Quaternary Science Reviews, 25 (19-20), pp. 2475-2502.

Arnold, L.J., Bailey, R.M., Tucher, G.E., 2007. Statistical treatment of fluvial dose distributions from southern Colorado arroyo deposits. Quaternary Geochronology, 2, pp.162-167.

Duller, G.A.T., 2008. Single-grain optical dating of Quaternary sediments: why aliquot size matters in luminescence dating. Boreas, 37 (4), pp.589-612.

Examples

Run this code

data(EDdata)
 dbED(EDdata$al3)