drc (version 1.2-0)

termec: Mechlorprop and terbythylazine tested on Lemna minor

Description

Data consist of 5 mixture, 6 dilutions, three replicates, and 12 common controls; in total 102 onservations.

Usage

data(termec)

source

The dataset is kindly provided by Nina Cedergreen, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Denmark.

Details

The dataset is analysed in S{\o}rensen et al (2006). The asymmetric Voelund model is appropriate, whereas the symmetric Hewlett model is not.

References

S{\o}rensen, H. and Cedergreen, N. and Skovgaard, I. M. and Streibig, J. C. (2006) An isobole-based statistical model and test for synergism/antagonism in binary mixture toxicity experiments, Statistical Ecology and Environmental Statistics, 13. ?--??.

Examples

## Fitting the concentration addition model
model1ca <- mixture(rgr1~dose1, pct1, data=termec, collapse=~1, 
fct=l3(), model="CA", boxcox=TRUE, bcAdd=0.02)
anova(model1ca)  # comparison to model with freely varying e parameter
summary(model1ca)


## Fitting the Hewlett model
model1h <- mixture(rgr1~dose1, pct1, data=termec, collapse=~1, 
fct=l3(), model="Hewlett", boxcox=TRUE, bcAdd=0.02)
anova(model1h)  # comparison to a model with freely varying e parameter
anova(model1ca, model1h)
summary(model1h)


## Fitting the Voelund model
model1v<-mixture(rgr1~dose1, pct1, data=termec, collapse=~1, 
fct=l3(), model="Voelund", boxcox=TRUE, bcAdd=0.02)
anova(model1v)  # comparison to a model with freely varying e parameter
summary(model1v)


rm(model1ca, model1h, model1v)