S.alba {drc} | R Documentation |
Data are from an experiment, comparing the potency of the two herbicides glyphosate and bentazone in white mustard Sinapis alba.
data(S.alba)
A data frame with 68 observations on the following 3 variables.
Dose
Herbicide
Bentazone
Glyphosate
(the two herbicides applied).DryMatter
The lower and upper limits for the two herbicides can be assumed identical, whereas slopes and ED50 values are different (in the log-logistic model).
Christensen, M. G. and Teicher, H. B., and Streibig, J. C. (2003) Linking fluorescence induction curve and biomass in herbicide screening, Pest Management Science, 59, 1303–1310.
See the examples in the examples sections in drm
and SI
.
## Fitting a log-logistic model with ## common lower and upper limits S.alba.m1 <- drm(DryMatter~Dose, Herbicide, data=S.alba, fct = LL.4(), pmodels=data.frame(Herbicide,1,1,Herbicide)) ## Applying the optimal transform-both-sides Box-Cox transformation S.alba.m2 <- boxcox(S.alba.m1, method = "anova") ## Plotting fitted regression curves together with the data plot(S.alba.m2)