chickwts              package:datasets              R Documentation

Chicken Weights by Feed Type

Description:

     An experiment was conducted to measure and compare the
     effectiveness of various feed supplements on the growth rate of
     chickens.

Usage:

     chickwts

Format:

     A data frame with 71 observations on 2 variables.

     weight a numeric variable giving the chick weight.

     feed a factor giving the feed type.

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.

Source:

     Anonymous (1948) _Biometrika_, *35*, 214.

References:

     McNeil, D. R. (1977) _Interactive Data Analysis_. New York: Wiley.

Examples:

     require(stats); require(graphics)
     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)

