

   RRiisskk FFaaccttoorrss ffoorr LLooww BBiirrtthh WWeeiigghhtt

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

        low: Indicator of low birth weight; `1' indicates low
             birth weight (< 2.5kg), `0' indicates normal birth
             weight.

        age: Mother's age in years at the time of birth.

        lwt: The mother's weight (in pounds) at the time of the
             last menstrual period.

       race: A factor for the mother's race. Levels are `1'
             (white), `2' (black) and `3' (other).

      smoke: Indicator of mother's smoking status; `1'=smoker,
             `0'=non-smoker.

        ptl: Number of previous premature labours.

         ht: Indicator of hypertension history; `1'=yes,
             `0'=no.

         ui: Indicator of the presence of uterine irritability;
             `1'=yes, `0'=no.

        ftv: Number of physician visits during the first
             trimester

        bwt: Infant's birth weight in grams

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

        The `birthwt' data frame has 189 rows and 10 columns.

        Data was collected at the Baystate Medical Center,
        Springfield, Massachusetts during 1986 to attempt to
        identify which factors contributed to an increased risk
        of low birth weight infants.  Information was recorded
        for 189 women of whom 59 had low birth weight infants.

   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

        Hosmer, D.W. and Lemeshow, S. (1989) Applied Logistic
        Regression.  John Wiley.

   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.

        Venables, W.N. and Ripley, B.D. (1994) Modern Applied
        Statistics with S-Plus. Springer-Verlag.

