Results from an Experiment on Plant Growth
Results from an experiment to compare yields (as measured by dried
weight of plants) obtained under a control and two different treatment
A data frame of 30 cases on 2 variables.
[, 1] || weight || numeric
[, 2] || group || factor
The levels of
group are ‘ctrl’, ‘trt1’, and ‘trt2’.
Dobson, A. J. (1983)
An Introduction to Statistical Modelling.
London: Chapman and Hall.
## One factor ANOVA example from Dobson's book, cf. Table 7.4:
boxplot(weight ~ group, data = PlantGrowth, main = "PlantGrowth data",
ylab = "Dried weight of plants", col = "lightgray",
notch = TRUE, varwidth = TRUE)
anova(lm(weight ~ group, data = PlantGrowth))