Insect Damages on Carrots
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.
data(carrots, package="robustbase")
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 B1 to B3
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 glmrob
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)) ....Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.