R: Growth of orange trees

Orange {nls} | 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.

### Format

This data frame contains 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.

### 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) Mixed-effects Models in S and S-PLUS, Springer.

### Examples

    data(Orange)
    coplot(circumference ~ age | Tree, data = Orange, show = 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, len = 101)
    lines(age, predict(fm1, list(age = age)))

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