jansen.apple.Rd
Infestation of apple shoots by apple canker.
data("jansen.apple")
A data frame with 36 observations on the following 5 variables.
inoculum
inoculum level
gen
genotype/variety
block
block
y
number of inoculations developing canker
n
number of inoculations
Shoots of apple trees were infected with fungus Nectria galligena, which may cause apple canker.
The incoulum density treatment had 3 levels, measured in macroconidia per ml.
There were 4 blocks.
Used with permission of J. Jansen. Electronic version supplied by Miroslav Zoric.
J. Jansen & J.A. Hoekstra (1993). The analysis of proportions in agricultural experiments by a generalized linear mixed model. Statistica Neerlandica, 47(3), 161-174. https://doi.org/10.1111/j.1467-9574.1993.tb01414.x
None.
# \dontrun{ library(agridat) data(jansen.apple) dat <- jansen.apple libs(lattice) xyplot(inoculum ~ y/n|gen, data=dat, group=block, layout=c(3,1), main="jansen.apple", xlab="Proportion infected per block/inoculum", ylab="Inoculum level")## libs(lme4) ## # Tentative model. Needs improvement. ## m1 <- glmer(cbind(y,n-y) ~ gen + factor(inoculum) + (1|block), ## data=dat, family=binomial) ## summary(m1) # }