fit_joint_2pLL: Fitting a 2pLL model

In jcduda/td2pLL: Fitting a time-dose two-parameter log-logistic model to time-dose-response data

Fitting a 2pLL model

Description

fit_joint_2pLL fits a 2pLL model. The "joint" is in the name because, despite being a regular 2pLL model, this function is used in the anova-td2pLL pipeline TDR(): If the anova pre-test, that checks if there is a difference in ED50 parameters between (exposure) times, is not significant, the exposure times are ignored. In other words, a single, 'joint', dose-response curve is fitted to the data, ignoring the information of exposure time.

Usage

fit_joint_2pLL(data)

Arguments

data	(data.frame()) Contains the dose and resp variable..

Details

The function is a wrapper function using the LL2.2() argument from the drc::drm() function with the fixed asymptotes upper=100 and lower=0. As a first try, the Nelder-Mead method is used as optimization procedure. If this yields an error, the BFGS method is used as opitmization method.

Value

An object of class drc.

Note

When using the LL2.2() model from the drc::drm() function, the ED50 parameter is parametrized as log(ED50). We do this for improved stability.

jcduda/td2pLL documentation built on May 14, 2022, 6:48 p.m.