Sitka {MASS} | R Documentation |

## Growth Curves for Sitka Spruce Trees in 1988

### Description

The `Sitka`

data frame has 395 rows and 4 columns. It gives repeated
measurements on the log-size of 79 Sitka spruce trees, 54 of which
were grown in ozone-enriched chambers and 25 were controls. The size
was measured five times in 1988, at roughly monthly intervals.

### Usage

Sitka

### Format

This data frame contains the following columns:

`size`

- measured size (height times diameter squared) of tree, on log scale
`Time`

- time of measurement in days since 1 January 1988
`tree`

- number of tree
`treat`

- either
`"ozone"`

for an ozone-enriched chamber or `"control"`

### Source

P. J. Diggle, K.-Y. Liang and S. L. Zeger (1994)
*Analysis of Longitudinal Data.*
Clarendon Press, Oxford

### References

Venables, W. N. and Ripley, B. D. (2002)
*Modern Applied Statistics with S.* Fourth edition. Springer.

### See Also

`Sitka89`

[Package

*MASS* version 7.2-23

Index]