Orange {MEMSS}

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

This data frame contains the following columns:

Tree

a factor indicating the tree on which the measurement is made.

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

require(lattice)
xyplot(circumference ~ age, Orange, groups = Tree, type = c("g", "b"),
       auto.key = list(space = "right", lines = TRUE), aspect = "xy",
       xlab = "Age (days since 1968/12/31)", ylab = "Circumference (mm)")
## Not run: 
m1 <- nlmer(circumference ~ SSlogis(age, Asym, xmid, scal) ~ Asym|Tree,
            Orange, verbose = TRUE,
            start = c(Asym = 190, xmid = 730, scal = 350))
.Call("mer_optimize", m1, 1L, 1L, PACKAGE = "lme4")
print(m1)
ranef(m1)

## End(Not run)