Girth, Height and Volume for Black Cherry Trees
This data set provides measurements of the girth, height and volume
of timber in 31 felled black cherry trees. Note that girth is the
diameter of the tree (in inches) measured at 4 ft 6 in above the
A data frame with 31 observations on 3 variables.
|| Tree diameter in inches
|| Height in ft
|| Volume of timber in cubic ft
Ryan, T. A., Joiner, B. L. and Ryan, B. F. (1976)
The Minitab Student Handbook.
Atkinson, A. C. (1985)
Plots, Transformations and Regression.
Oxford University Press.
pairs(trees, panel = panel.smooth, main = "trees data")
plot(Volume ~ Girth, data = trees, log = "xy")
coplot(log(Volume) ~ log(Girth) | Height, data = trees,
panel = panel.smooth)
summary(fm1 <- lm(log(Volume) ~ log(Girth), data = trees))
summary(fm2 <- update(fm1, ~ . + log(Height), data = trees))
## i.e., Volume ~= c * Height * Girth^2 seems reasonable