numeric vector specifying which parameters are fixed and at what value they are fixed.
NAs are used for parameters that are not fixed.
names
a vector of character strings giving the names of the parameters (should not contain ":").
The default is reasonable (see under 'Usage').
fctName
optional character string used internally by convenience functions.
fctText
optional character string used internally by convenience functions.
Value
The value returned is a list containing the nonlinear function, the self starter function
and the parameter names.
Details
Following Wheeler and Bailer (2009) the model function is defined as follows:
$$f(x) = c + (d-c) * pgamma(b*x, e, 1)$$
This model is only suitable for increasing dose-response data.
References
Wheeler, M. W., Bailer, A. J. (2009)
Comparing model averaging with other model selection strategies for benchmark dose estimation,
Environmental and Ecological Statistics, 16, 37--51.
See Also
The basic component in the two-phase model is the log-logistic model
llogistic.