Ask about statistics data in oracle 9i

Hi all,

   My db is 9.2.0.4 run on AIX 5.3 64 bit.

   I use bellow script to gather statistic. Ok, when select from DBA_TAB_COL_STATISTICS from the LAST_ANALYZED I can view my table gathered. But I wonder that where are these statistics data store ? And Do I need delete them ?

begin
  dbms_stats.gather_table_stats(
       ownname           => 'XBANK',
       tabname             => 'T_LOG',
       estimate_percent  => dbms_stats.auto_sample_size,
       method_opt        => 'for all columns size auto',
       cascade           => true,
       degree            => 7
   );
end;

  Thanks.