stat_SDprop: Propagation of errors for isotope ratios

In MartinSchobben/point: Reading, Processing, and Analysing Raw Ion Count Data

Propagation of errors for isotope ratios

Description

stat_SDprop function for propagation of descriptive and predictive (Poisson) error statistics for isotope ratios (R).

Usage

stat_SDprop(ion1, ion2, type = "sd", predicted = FALSE)

Arguments

ion1	A numeric vector constituting the single ion count rate of the heavy isotope if argument predicted is set to FALSE, otherwise counts are required.
ion2	A numeric vector constituting the single ion count rate of the light isotope if argument predicted is set to FALSE, otherwise counts are required.
type	A character string for the type of uncertainty estimate: "sd", standard deviation; "rsd", relative standard deviation in per mille; "se", standard error of the mean; "rse", relative standard error of the mean in per mille.
predicted	Logical indicating whether sd is descriptive FALSE, or based on predicted Poisson value TRUE.

Details

Isotope ratios are based on two measured variables, i.e., two isotopes of a single chemical species. The combined variable compounds the uncertainty associated with the individual measurement. Hence error propagation is required to obtain a reliable estimate of the uncertainty associated with the compounded variable (i.e. isotope ratio).

Value

A numeric vector containing the propagated uncertainty of the isotope ratio.

Examples

# Light isotope count rates
`32S` <- c(22318.19, 22151.20, 22429.52, 22143.78, 22574.25, 22455.50)

# Heavy isotope count rate
`34S` <- c(231.4838, 220.3725, 255.5584, 237.0395, 244.4471, 238.8914)

# Propagation
stat_SDprop(`34S`, `32S`, "rse")

MartinSchobben/point documentation built on May 22, 2022, 7:15 a.m.