R: Fractional polynomial-logistic dose-response models

fplogistic {drc} | R Documentation

## Fractional polynomial-logistic dose-response models

### Description

Model function for specifying dose-response models that are a combination of a logistic model and an appropriate class of fractional polynomials.

### Usage

    fplogistic(p1, p2, fixed = c(NA, NA, NA, NA), names = c("b", "c", "d", "e"),
    method = c("1", "2", "3", "4"), ssfct = NULL, fctName, fctText)

    FPL.4(p1, p2, fixed = c(NA, NA, NA, NA), names = c("b", "c", "d", "e"), ...)

### Arguments

`p1` | numeric denoting the negative power of log(dose+1) in the fractional polynomial.
`p2` | numeric denoting the positive power of log(dose+1) in the fractional polynomial.
`fixed` | numeric vector. Specifies which parameters are fixed and at what value they are fixed. NAs for parameter 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'). The order of the parameters is: b, c, d, e, f (see under 'Details').
`method` | character string indicating the self starter function to use.
`ssfct` | a self starter function to be used.
`fctName` | optional character string used internally by convenience functions.
`fctText` | optional character string used internally by convenience functions.
`...` | Additional arguments (see `fplogistic`).

### Details

The fractional polynomial dose-response models introduced by Namata et al. (2008) are implemented using the logistic model as base.

### Value

The value returned is a list containing the nonlinear function, the self starter function and the parameter names.

### Author(s)

Christian Ritz

### References

Namata, Harriet and Aerts, Marc and Faes, Christel and Teunis, Peter (2008) Model Averaging in Microbial Risk Assessment Using Fractional Polynomials, Risk Analysis 28, 891–905.

### See Also

Examples are found `maED`.

[Package drc version 3.0-1 Index]