Working with Oracle and am getting a snapshot to old ora-1555 error.

I tried set transaction use rollback segment, but it does not appear as if analyze uses the transactions rollback segment as I specified.

here is my output

23:53:58 SQL> set transaction use rollback segment rollback_statistics;

Transaction set.

23:53:58 SQL> analyze table pmadmin.PM_CLK_HIS compute statistics;
analyze table pmadmin.PM_CLK_HIS compute statistics
ERROR at line 1:
ORA-01555: snapshot too old: rollback segment number 10 with name "RBS09" too small

Any help or ideas on work arounds?