R Dataset / Package MASS / Sitka89

On this R-data statistics page, you will find information about the Sitka89 data set which pertains to Growth Curves for Sitka Spruce Trees in 1989. The Sitka89 data set is found in the MASS R package. You can load the Sitka89 data set in R by issuing the following command at the console data("Sitka89"). This will load the data into a variable called Sitka89. If R says the Sitka89 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 Sitka89 R data set. The size of this file is about 12,943 bytes.

Growth Curves for Sitka Spruce Trees in 1989

Description

The Sitka89 data frame has 632 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 eight times in 1989, at roughly monthly intervals.

Usage

Sitka89

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

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