An experiment was conducted to measure and compare the effectiveness of various feed supplements on the growth rate of chickens.
A data frame with 71 observations on the following 2 variables.
a numeric variable giving the chick weight.
a factor giving the feed type.
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.
Anonymous (1948) Biometrika, 35, 214.
McNeil, D. R. (1977) Interactive Data Analysis. New York: Wiley.
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)