The R Project SVN R

\name{chickwts}
\title{Chicken Weights by Feed Type}
\usage{data(chickwts)}
\alias{chickwts}
\format{A data frame with 71 observations on 2 variables.
  \tabular{rlll}{
    [1,]  \tab weight  \tab numeric  \tab Chick weight \cr
    [2,]  \tab feed    \tab factor   \tab Feed type
  }
}
\source{
  Anonymous (1948).  \emph{Biometrika}, p.214.
} 
\description{
  An experiment was conducted to measure and compare the effectiveness
  of various feed supplements on the growth rate of chickens.
}
\details{
  Newly hatched chicks were randomly allocated into six groups, and each
  group was given a different feed supplement.  Their weights in grams
  after six weeks are given along with feed types.
}
\references{
  McNeil, D. R. (1977). \emph{Interactive Data Analysis}.  New York:
  Wiley.
}
\examples{
data(chickwts)
boxplot(weight ~ feed, data = chickwts, col = "lightgray",
    varwidth = TRUE, notch = TRUE, main = "chickwt data",
    ylab = "Weight at six weeks (gm)")
anova(fm1 <- lm(weight ~ feed, data = chickwts))
opar <- par(mfrow = c(2, 2), oma = c(0, 0, 1.1, 0),
            mar = c(4.1, 4.1, 2.1, 1.1))
plot(fm1)
par(opar)
\keyword{datasets}