Two-parameter asymptotic regression model

A two-parameter asymptotic regression model where b is fixed at 1 and the lower limit is fixed at 0. The model is given by the equation $$f(x) = d \cdot (1 - \exp(-x / e))$$

Usage

AR.2(fixed = c(NA, NA), names = c("d", "e"), ...)

Arguments

fixed

numeric vector of length 2, specifying fixed parameters (use NA for parameters that should be estimated).

names

character vector of length 2 giving the names of the parameters (default c("d", "e")).

...

additional arguments passed to weibull2, most notably method (a character string: "1" (default), "2", "3", or "4") which selects the self-starter method for obtaining starting values. See weibull2 for details.

Value

A list of class "Weibull-2" as returned by weibull2.

See also

AR.3, weibull2, EXD.2

Examples

ryegrass.m1 <- drm(rootl ~ conc, data = ryegrass, fct = AR.2())