lin.fit: Linear concentration - time model

In gasfluxes: Greenhouse Gas Flux Calculation from Chamber Measurements

Linear concentration - time model

Description

Fit a linear model to concentration - time data.

Usage

lin.fit(t, C, A = 1, V, serie = "", verbose = TRUE, plot = FALSE, ...)

Arguments

t	time values (usually in hours)
C	concentration values
A	area covered by the chamber
V	effective volume of the chamber
serie	id of the flux measurement
verbose	logical, TRUE prints message after each flux calculation
plot	logical, mainly intended for use in gasfluxes
...	further parameters, currently none

Details

This is basically a wrapper of R's OLS fitting facilities. For now lm (and methods for objects of class "lm") is used, but this may change to more efficient alternatives in later versions.

Value

A list of

f0	flux estimate
f0.se	standard error of flux estimate
f0.p	p-value of flux estimate
C0	estimated concentration at t = 0 (intercept)
AIC	Akaike information criterion
AICc	Akaike information criterion with small sample correction
RSE	residual standard error (sigma from summary.nls)
r	Pearson's correlation coefficient
diagnostics	error or warning messages

Examples

#a single fit
t <- c(0, 1/3, 2/3, 1)
C <- c(320, 341, 352, 359)
print(fit <- lin.fit(t, C, 1, 0.3, "a"))
plot(C ~ t)
curve({fit$f0/0.3 * x + fit$C0}, from = 0, to = 1, add = TRUE)

gasfluxes documentation built on Sept. 11, 2024, 6:09 p.m.