gasfluxes (version 0.7)

lin.fit: 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, ...)

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

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.

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)