Cuckoo Eggs Data

Description

Length and breadth measurements of 120 eggs lain in the nests of six different species of host bird.

Usage

cuckoos

Format

This data frame contains the following columns:

length

the egg lengths in millimeters

breadth

the egg breadths in millimeters

species

a factor with levels hedge.sparrow, meadow.pipit, pied.wagtail, robin, tree.pipit, wren

id

a numeric vector

Source

Latter, O.H. (1902). The eggs of Cuculus canorus. An Inquiry into the dimensions of the cuckoo's egg and the relation of the variations to the size of the eggs of the foster-parent, with notes on coloration, &c. Biometrika i, 164. Tippett (1931) gives summary details of the data.

References

Tippett, L.H.C. 1931: "The Methods of Statistics". Williams & Norgate, London.

Examples

 
print("Strip and Boxplots - Example 2.1.2")

attach(cuckoos)
oldpar <- par(las = 2) # labels at right angle to axis.
stripchart(length ~ species) 
boxplot(split(cuckoos$length, cuckoos$species),
         xlab="Length of egg", horizontal=TRUE)
detach(cuckoos)
par(oldpar)
pause()

print("Summaries - Example 2.2.2")
sapply(split(cuckoos$length, cuckoos$species), sd)
pause()

print("Example 4.1.4")
wren <- split(cuckoos$length, cuckoos$species)$wren
median(wren)
n <- length(wren)
sqrt(pi/2)*sd(wren)/sqrt(n)  # this s.e. computation assumes normality