

   SShheeaatthheerr--JJoonneess cchhooiiccee ooff ssmmooootthhiinngg ppaarraammeetteerr ffoorr ddeennssiittyy
   eessttiimmaattiioonn

        hsj(x)

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

          x: a vector of data.

   DDeessccrriippttiioonn::

        This function uses the Sheather-Jones plug-in method of
        selecting a smoothing parameter which is suitable for
        constructing a density estimate in the one-dimensional
        case.

   DDeettaaiillss::

        see Section 2.4.4 of the reference below.

   VVaalluuee::

        the value of the smoothing parameter localted by the
        Sheather-Jones method.

   SSiiddee EEffffeeccttss::

        none.

   RReeffeerreenncceess::

        Bowman, A.W. and Azzalini, A. (1997). Applied Smoothing
        Techniques for Data Analysis: the Kernel Approach with
        S-Plus Illustrations.  Oxford University Press, Oxford.

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

        `hnorm', `hcv'

   EExxaammpplleess::

        x <- rnorm(50)
        hsj(x)

