A few things to discuss here
1) ANALYZE TABLE COMPUTE STATISTICS;
Don’t use this command. It is obsolete. It is designed to collect information on the table to allow queries against it to be run in the best fashion. Use DBMS_STATS.GATHER_TABLE_STATS instead. And that’s just an obvious lead in to that you should have a good read of the Performance Tuning guide to get your head around the optimizer, SQL execution etc
2) Rebuild index
Nothing to do with the table at all. It is about re-generating the structure that is used for certain queries to efficiently access table data. It is rare that rebuilds are required. If you are interested in that, there’s a very good whitepaper at
solved What’s the difference between analyzing a table and rebuilding the index in oracle SQL?