Make relative frequency plots for all input variables after (final) box
selection for current rule:

relfreq (plt=1, nc=4)

Optional arguments:

   plt = flag for quantity plotted:
      plt = 1 => plot relative (box/global) frequencies,
      plt = 2 => plot lower bin limits for each relative frequency plot.
   nc = number of columns for plot matrix.

Examples:

   relfreq()
   relfreq(2)
   relfreq(nc=3)

Remarks:

   This function can be invoked from the S command prompt (>) after the
   SuperGEM dialog window message/prompt

      Relative frequency plots {>relfreq()}.
      Continue covering? (<cr> = yes)

   is issued. It produces relative frequency plots for all input variables
   associated with the current (just constructed) box. The plots must be made
   before responding to this SuperGEM prompt. Relative frequency plots are
   described in Friedman and Fisher (1997), Section 16.2. They can be 
   interpreted and/or saved (from S) before proceeding on to construct the next
   rule, or quitting supgem(). Relative frequency plots (in tabular form) are
   always included in the rule summary (see "rules").

   Responding to the prompt with y, yes or a <cr> causes the  iterative
   covering procedure to continue for another iteration. Any other response
   terminates the covering procedure and closes the SuperGEM dialog window.