fit4plModel {logicDT}

Fitting 4pL models

Description

Method for fitting four parameter logistic models. In the fashion of this package, only binary and quantitative outcomes are supported.

Usage

fit4plModel(y, Z)

Arguments

y

Response vector. 0-1 coding for binary outcomes, otherwise conventional regression is performed.

Z

Numeric vector of (univariate) input samples.

Details

4pL models are non-linear regression models of the shape

Y = f(x, b, c, d, e) + \varepsilon = c + \frac{d-c}{1+\exp(b \cdot (x-e))} + \varepsilon

with \varepsilon being a random error term.

Value

An object of class "4pl" which contains a numeric vector of the fitted parameters b, c, d, and e.