case1002: The Energy Costs of Echolocation by Bats

In Sleuth2: Data Sets from Ramsey and Schafer's "Statistical Sleuth (2nd Ed)"

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))

Example output

'data.frame':	20 obs. of  4 variables:
 $ Species: chr  "Pteropus gouldii" "Pteropus poliocephalus" "Hypsignathus monstrosus" "Eidolon helvum" ...
 $ Mass   : num  779 628 258 315 24.3 ...
 $ Type   : Factor w/ 3 levels "non-echolocating bats",..: 1 1 1 1 2 2 2 2 2 2 ...
 $ Energy : num  43.7 34.8 23.3 22.4 2.46 ...

Sleuth2 documentation built on May 2, 2019, 7:01 a.m.