

   WWaatteerr SSaalliinniittyy aanndd RRiivveerr DDiisscchhaarrggee..

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

        sal: The average salinity of the water over two weeks.

        lag: The average salinity of the water lagged two
             weeks.  Since only spring is used, the value of
             `lag' is not always equal to the previous value of
             `sal'.

      trend: A factor indicating in which of the 6 biweekly
             periods between March and May, the observations
             were taken. The levels of the factor are from 0 to
             5 with 0 being the first two weeks in March.

        dis: The amount of river discharge during the two weeks
             for which `sal' is the average salinity.

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

        The `salinity' data frame has 28 rows and 4 columns.

        Biweekly averages of the water salinity and river dis-
        charge in Pamlico Sound, North Carolina were recorded
        between the years 1972 and 1977.  The data in this set
        consists only of those measurements in March, April and
        May.

   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::

        The data were obtained from

        Ruppert, D. and Carroll, R.J. (1980) Trimmed least
        squares estimation in the linear model.  Journal of the
        American Statistical Association, 75, 828-838.

   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.

