Mammals {quantreg} | R Documentation

## Garland(1983) Data on Running Speed of Mammals

### Description

Observations on the maximal running speed of mammal species and their body mass.

### Usage

    data(Mammals)

### Format

A data frame with 107 observations on the following 4 variables.

weight

  Body mass in Kg for "typical adult sizes"

speed

  Maximal running speed (fastest sprint velocity on record)

hoppers

  logical variable indicating animals that ambulate by hopping, e.g. kangaroos

specials

  logical variable indicating special animals with "lifestyles in which speed does not figure as an important factor": Hippopotamus, raccoon (Procyon), badger (Meles), coati (Nasua), skunk (Mephitis), man (Homo), porcupine (Erithizon), oppossum (didelphis), and sloth (Bradypus)

### Details

Used by Chappell (1989) and Koenker, Ng and Portnoy (1994) to illustrate the fitting of piecewise linear curves.

### Source

Garland, T. (1983) The relation between maximal running speed and body mass in terrestrial mammals, J. Zoology, 199, 1557-1570.

### References

Koenker, R., P. Ng and S. Portnoy, (1994) Quantile Smoothing Splines” Biometrika, 81, 673-680.

Chappell, R. (1989) Fitting Bent Lines to Data, with Applications ot Allometry, J. Theo. Biology, 138, 235-256.

### See Also

`rqss`

### Examples

    data(Mammals)
    attach(Mammals)
    x <- log(weight)
    y <- log(speed)
    plot(x,y, xlab="Weight in log(Kg)", ylab="Speed in log(Km/hour)",type="n")
    points(x[hoppers],y[hoppers],pch = "h", col="red")
    points(x[specials],y[specials],pch = "s", col="blue")
    others <- (!hoppers & !specials)
    points(x[others],y[others], col="black",cex = .75)
    fit <- rqss(y ~ qss(x, lambda = 1),tau = .9)
    plot(fit)

[Package quantreg version 5.33 Index]