robustbase (version 0.5-0-1)

carrots: Insect Damages on Carrots

Description

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.

Usage

data(carrots)

source

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.

References

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

Examples

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)) ....