case1002 {Sleuth2}

The Energy Costs of Echolocation by Bats

Description

The data are on in–flight energy expenditure and body mass from 20 energy studies on three types of flying vertebrates: echolocating bats, non–echolocating bats and non–echolocating birds.

Usage

case1002

Format

A data frame with 20 observations on the following 4 variables.

Species

species

Mass

mass (in grams)

Type

a factor with 3 levels indicating the type of flying vertebrate

Energy

in–flight energy expenditure (in W)

Source

Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.

References

Speakman, J.R. and Racey, P.A. (1991). No cost of Echolocation for Bats in Flight, Nature 350: 421–423.

Examples

str(case1002)

plot(log(Energy)~log(Mass), case1002,
     pch = ifelse(Type=="echolocating bats", 19,
                  ifelse(Type=="non-echolocating birds", 21, 24)))

plot(Energy~Mass, case1002, log="xy",
     xlab = "Body Mass (g) (log scale)",
     ylab = "Energy Expenditure (W) (log scale)", 
     pch = ifelse(Type=="echolocating bats", 19,
                  ifelse(Type=="non-echolocating birds", 21, 24)))
legend(7, 50, pch=c(24, 21, 19),
     c("Non-echolocating bats", "Non-echolocating birds","Echolocating bats"))

library(lattice)
yticks <- c(1,2,5,10,20,50)
xticks <- c(10,20,50,100,200,500)
xyplot(Energy ~ Mass, case1002, groups=Type, 
       scales = list(log=TRUE, y=list(at=yticks), x=list(at=xticks)),
       ylab = "Energy Expenditure (W) (log scale)",
       xlab = "Body Mass (g) (log scale)", 
       auto.key = list(x = 0.2, y = 0.9, corner = c(0, 1), border = TRUE))