leafblotch {GLMsData}

Percentage leaf area of leaf blotch

Description

The percentage leaf area of barley infected with leafblotch

Usage

data(leafblotch)

Format

A data frame with 90 observations on the following 3 variables.

Area

the percentage area infected with leaf blotch; a numeric vector

Site

the site; a factor with levels A, B up to I

Variety

the variety of barley; a factor with levels 1, 2, up to 9

Details

The data give the percentage leaf area of barley infected with Rhynchosporium secalis, or leaf blotch, for ten different barley varieties grown at nine different sites.

Source

R. W. M. Wedderburn (1974) Quasi-likelihood functions, generalized linear models, and the Gauss-Newton method. Biometrika, 61(3), 439–447.

References

The data also appear in McCullagh and Nelder, p 329, and in Faraway (2006), Exercise 7.5.

Examples

data(leafblotch)
plot( Area ~ Site, data=leafblotch)