Sitka89                 package:MASS                 R Documentation

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

See Also:

     'Sitka'

