R Dataset / Package MASS / Sitka

On this R-data statistics page, you will find information about the Sitka data set which pertains to Growth Curves for Sitka Spruce Trees in 1988. The Sitka data set is found in the MASS R package. You can load the Sitka data set in R by issuing the following command at the console data("Sitka"). This will load the data into a variable called Sitka. If R says the Sitka data set is not found, you can try installing the package by issuing this command install.packages("MASS") and then attempt to reload the data with the library() command. If you need to download R, you can go to the R project website. You can download a CSV (comma separated values) version of the Sitka R data set. The size of this file is about 8,084 bytes.

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.

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