Orange  R Documentation 
Growth of Orange Trees
Description
The Orange
data frame has 35 rows and 3 columns of records of
the growth of orange trees.
Usage
Orange
Format
An object of class
c("nfnGroupedData", "nfGroupedData", "groupedData", "data.frame")
containing the following columns:
 Tree

an ordered factor indicating the tree on which the measurement is made. The ordering is according to increasing maximum diameter.
 age

a numeric vector giving the age of the tree (days since 1968/12/31)
 circumference

a numeric vector of trunk circumferences (mm). This is probably “circumference at breast height”, a standard measurement in forestry.
Details
This dataset was originally part of package nlme
, and that has
methods (including for [
, as.data.frame
, plot
and
print
) for its groupeddata classes.
Source
Draper, N. R. and Smith, H. (1998), Applied Regression Analysis (3rd ed), Wiley (exercise 24.N).
Pinheiro, J. C. and Bates, D. M. (2000) Mixedeffects Models in S and SPLUS, Springer.
Examples
require(stats); require(graphics)
coplot(circumference ~ age  Tree, data = Orange, show.given = FALSE)
fm1 < nls(circumference ~ SSlogis(age, Asym, xmid, scal),
data = Orange, subset = Tree == 3)
plot(circumference ~ age, data = Orange, subset = Tree == 3,
xlab = "Tree age (days since 1968/12/31)",
ylab = "Tree circumference (mm)", las = 1,
main = "Orange tree data and fitted model (Tree 3 only)")
age < seq(0, 1600, length.out = 101)
lines(age, predict(fm1, list(age = age)))