drc: daphnids – R documentation

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daphnids

Daphnia test

Description

The number of immobile daphnids –in contrast to mobile daphnids– out of a total of 20 daphnids was counted for several concentrations of a toxic substance.

Usage

data(daphnids)

Format

A data frame with 16 observations on the following 4 variables.

dose: a numeric vector
no: a numeric vector
total: a numeric vector
time: a factor with levels 24h 48h

Details

The same daphnids were counted at 24h and later again at 48h.

Source

Nina Cedergreen, Faculty of Life Sciences, University of Copenhagen, Denmark.

Examples

## Fitting a model with different parameters
## for different curves
daphnids.m1 <- drm(no/total~dose, time, weights = total, 
data = daphnids, fct = LL.2(), type = "binomial")

## Goodness-of-fit test
modelFit(daphnids.m1)

## Summary of the data
summary(daphnids.m1)

## Fitting a model with a common intercept parameter
daphnids.m2 <- drm(no/total~dose, time, weights = total, 
data = daphnids, fct = LL.2(), type = "binomial", 
pmodels = list(~1, ~time))

drc

Analysis of Dose-Response Curves

v3.0-1

GPL-2 | file LICENCE

Authors

Christian Ritz <ritz@bioassay.dk>, Jens C. Strebig <streibig@bioassay.dk>

Initial release

2016-08-25