

   AAnnnnuuaall MMeeaann SSuunnssppoott NNuummbbeerrss

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

        `sunspot' is a time series of class `"rts"' and con-
        tains 289 observations.

        The Zurich sunspot numbers have been analyzed in almost
        all books on time series analysis as well as numerous
        papers.  The data set, usually attributed to Rudolf
        Wolf, consists of means of daily relative numbers of
        sunspot sightings.  The relative number for a day is
        given by k(f+10g) where g is the number of sunspot
        groups observed, f is the total number of spots within
        the groups and k is a scaling factor relating the
        observer and telescope to a baseline. The relative num-
        bers are then averaged to give an annual figure.  See
        Insenman (1983) for a discussion of the relative num-
        bers. The figures are for the years 1700-1988.

   NNOOTTEE::

        These data are not related to dataset of the same name
        in the `trellis' library.  They are, however, similar
        to the `S-Plus' dataset `sunspots' except that this set
        contains annual averages instead of monthly averages
        and it is for a longer period of time.

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

        The data were obtained from

        Tong, H. (1990) Nonlinear Time Series: A Dynamical Sys-
        tem Approach.  Oxford University Press

   OOTTHHEERR RREEFFEERREENNCCEESS::

        Davison, A.C. and Hinkley, D.V. (1997) Bootstrap Meth-
        ods and Their Application. Cambridge University Press.

        Inzenman, A.J. (1983) J.R. Wolf and H.A. Wolfer: An
        historical note on the Zurich sunspot relative numbers.
        Journal of the Royal Statistical Society, A, 146,
        311-318.

        Waldmeir, M. (1961) The Sunspot Activity in the Years
        1610-1960.  Schulthess and Co.

