Few examples:
exec dbms_stats.SET_GLOBAL_PREFS('AUTOSTATS_TARGET', 'AUTO');
exec dbms_stats.SET_DATABASE_PREFS('STALE_PERCENT', '15');
exec dbms_stats.GATHER_DATABASE_STATS(degree => 4, cascade => TRUE);
exec dbms_stats.GATHER_SCHEMA_STATS(ownname => 'SCOTT', degree => 4, cascade => TRUE);
exec dbms_stats.GATHER_TABLE_STATS(ownname => 'SCOTT', tabname => 'EMP', degree => 4, cascade => TRUE);
Moid