termec {drc} | R Documentation |
Data consist of 5 mixture, 6 dilutions, three replicates, and 12 common controls; in total 102 onservations.
data(termec)
A data frame with 102 observations on the following 4 variables.
cell
dose1
pct1
rgr1
The dataset is analysed in S{o}rensen et al (2006). The asymmetric Voelund model is appropriate, whereas the symmetric Hewlett model is not.
The dataset is kindly provided by Nina Cedergreen, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Denmark.
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. ?–??.
## 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)