

   GGrroowwtthh CCuurrvveess ffoorr SSiittkkaa SSpprruuccee TTrreeeess iinn 11998899

   AArrgguummeennttss::

       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"'

   SSUUMMMMAARRYY::

        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 inter-
        vals.

   DDAATTAA DDEESSCCRRIIPPTTIIOONN::

        This data frame contains the following columns:

   SSOOUURRCCEE::

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

   SSeeee AAllssoo::

        `Sitka'

