quantreg (version 4.77)

Mammals: 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)

source

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

Details

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

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)