drc (version 0.9-0)

mixdrc: Fitting multiple dose-response curves with random effects

Description

'mixdrc' fits non-linear mixed models where random effects are assigned to some or all of the parameters.

Usage

mixdrc(object, random, data)

Arguments

object

an object of class 'drc'.

random

a character string specifying the random effects. Specification is as in nlme.

data

a data frame containing the variables in the model (not optional).

Value

• An object of classes 'drc' and 'nlme'.

Details

The function searches through a range of initial values in order to obtain convergence of the estimation procedure.

Examples

## First fitting model without random effects
model1 <- multdrc(SLOPE~DOSE, CURVE, data=PestSci,
collapse=data.frame(HERBICIDE, 1, 1, HERBICIDE))

## Then fitting model with random effects (assigned to d)
model2 <- mixdrc(model1, random="d~1|CURVE", data=PestSci)
compParm(model2, "e", "-")

## First fitting model without random effects
##  but with a Box-Cox transformation
model3 <- multdrc(SLOPE~DOSE, CURVE, data=PestSci,
collapse=data.frame(HERBICIDE, 1, 1, HERBICIDE), boxcox=TRUE)

## Then fitting model with random effects (assigned to d)
model4 <- mixdrc(model3, random="d~1|CURVE", data=PestSci)
compParm(model4, "e", "-")


rm(model1, model2, model3, model4)