Spruce {nlme} | R Documentation |

## Growth of Spruce Trees

### Description

The `Spruce`

data frame has 1027 rows and 4 columns.

### Format

This data frame contains the following columns:

- Tree
- a factor giving a unique identifier for each tree.
- days
- a numeric vector giving the number of days since the
beginning of the experiment.
- logSize
- a numeric vector giving the logarithm of an estimate of the
volume of the tree trunk.
- plot
- a factor identifying the plot in which the tree was grown.

### Details

Diggle, Liang, and Zeger (1994, Example 1.3, page 5)
describe data on the growth of spruce trees that have been exposed to
an ozone-rich atmosphere or to a normal atmosphere.

### Source

Pinheiro, J. C. and Bates, D. M. (2000), *Mixed-Effects Models in S
and S-PLUS*, Springer, New York. (Appendix A.28)

Diggle, Peter J., Liang, Kung-Yee and Zeger, Scott L. (1994),
*Analysis of longitudinal data*, Oxford University Press,
Oxford.

[Package

*nlme* version 3.1-57

Index]