Four-parameter Weibull type 2 model with lag time — W2x.4 • drc

A four-parameter Weibull type 2 model with lag time, where b is fixed at 1. This is a convenience wrapper around weibull2x.

Usage

W2x.4(fixed = c(NA, NA, NA, NA), names = c("c", "d", "e", "t0"), ...)

Arguments

fixed: numeric vector of length 4. Specifies which parameters are fixed and at what value. Use NA for parameters that should be estimated (default is c(NA, NA, NA, NA)).
names: character vector of length 4 giving the names of the parameters (default is c("c", "d", "e", "t0")).
...: additional arguments passed to weibull2x.

Value

A list of class "Weibull-2" containing the nonlinear function, self starter function, and parameter names.

See also

weibull2x, W2x.3, W2.4

Examples

ryegrass.m1 <- drm(rootl ~ conc, data = ryegrass, fct = W2x.4())
#> Warning: NaNs produced
#> Warning: NaNs produced