cow: Data from an Experiment with Treatment Assignment Based on...
In BayesDA: Functions and Datasets for the book "Bayesian Data Analysis"

Description Usage Format Examples

An experiment was conducted on 50 cows to estimate the effect of a feed additive (methionine hydroxy analog) on six outcomes related to the amount of milk fat produced by each cow. Four diets (treatments) were considered, corresponding to different levels of the additive, and three variables were recorded before treatment assignment: lactation number ( seasons of lactation), age, and initial weight of cow. Multiple randomizations were calculated, and choosen that one with ‘best balane’, however that was defined.

data(cow)

A data frame with 50 observations on the following 10 variables.

level: diet, treatment
lactation: lactation number, pretreatment
age: age of cow, pretreatment variable
initial.weight: initial weight, pretreatment
dry: response
milk: response
fat: response
solids: response
final.weight: response
protein: response

data(cow)
summary(cow)
names(cow)
# Investigating balance on pretreatment variables:
with(cow, tapply(lactation, level, mean))
with(cow, tapply(age, level, mean))