The damage carrots data set from Phelps (1982) was used by McCullagh and Nelder (1989) in order to illustrate diagnostic techniques because of the presence of an outlier. In a soil experiment trial with three blocks, eight levels of insecticide were applied and the carrots were tested for insect damage.
A data frame with 24 observations on the following 4 variables.
integer giving the number of carrots with insect damage.
integer giving the total number of carrots per experimental unit.
a numeric vector giving log(dose) values (eight different levels only).
factor with levels
Phelps, K. (1982).
Use of the complementary log-log function to describe doseresponse
relationships in insecticide evaluation field trials.
In R. Gilchrist (Ed.), Lecture Notes in Statistics, No. 14. GLIM.82: Proceedings of the International Conference on Generalized Linear Models; Springer-Verlag.
McCullagh P. and Nelder, J. A. (1989) Generalized Linear Models. London: Chapman and Hall.
Eva Cantoni and Elvezio Ronchetti (2001); JASA, and
Eva Cantoni (2004); JSS, see
data(carrots) str(carrots) plot(success/total ~ logdose, data = carrots, col = as.integer(block)) coplot(success/total ~ logdose | block, data = carrots) ## Classical glm Cfit0 <- glm(cbind(success, total-success) ~ logdose + block, data=carrots, family=binomial) summary(Cfit0) ## Robust Fit (see help(glmrob)) ....