butterfat {GLMsData}

Butterfat and dairy cattle

Description

The average butterfat content for dairy cattle

Usage

data(butterfat)

Format

A data frame with 100 observations on the following 3 variables.

Butterfat

the average butterfat percentage; a numeric vector

Breed

the cattle breed; a factor with levels Ayrshire, Canadian, Guernsey, Holstein-Fresian and Jersey

Age

the age of the cow; a factor with levels 2year and Mature

Details

The data give the average butterfat content (percentages) for random samples of twenty cows (ten two-year old and ten mature (greater than four years old)) from each of five breeds. The data are from Canadian records of pure-bred dairy cattle.

Source

D. J. Hand, F. Daly, A. D. Lunn, K. J. McConway, and E. Ostrowski (1994) A Handbook of Small Data Sets, London: Chapman and Hall. Dataset 23.

R. R. Sokal and F. J. Rohlf (1981) Biometry, 2nd edition, San Fransisco: WH Freeman.

Examples

data(butterfat)
summary(butterfat)