The data gives the proportion of leaf area affected by leaf blotch on 10 varieties of barley at 9 different sites.
data(leafblotch)
A data frame with 90 observations on the following 3 variables.
blotch
proportion of the barley leaf affected by blotch
site
the physical location - a factor with levels 1
2
3
4
5
6
7
8
9
variety
variety of barley - a factor with levels 1
2
3
4
5
6
7
8
9
10
P. McCullagh and J. Nelder (1989) "Generalized Linear Models" Chapman and Hall, 2nd ed.