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.

### Examples

    data(Spruce)

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