SQL> create table stat (i integer, j integer, k integer);

Table created.

SQL> insert into stat select rownum, rownum, rownum
   2   from dba_objects, dba_objects where rownum <=  1000000 ;

 1000000  rows created.

SQL> create index stat_i on stat (i);

Index created.

SQL> select max(j) from stat where i<= 10 ;

Execution Plan
----------------------------------------------------------                      
    0       SELECT STATEMENT Optimizer=CHOOSE (Cost= 4  Card= 1  Bytes= 10 )            
    1      0    SORT (AGGREGATE)                                                    
    2      1      TABLE ACCESS (BY INDEX ROWID) OF 'STAT' (Cost= 4  Card= 10            
          Bytes= 100 )                                                            
                                                                                
    3      2        INDEX (RANGE SCAN) OF 'STAT_I' (NON-UNIQUE) (Cost= 3  Ca          
          rd= 10 )                                                                

Statistics
----------------------------------------------------------                      
           4   consistent gets                                                    

SQL> select max(j) from stat where i<= 900000 ;

Execution Plan
----------------------------------------------------------                      
    0       SELECT STATEMENT Optimizer=CHOOSE (Cost= 169  Card= 1  Bytes= 10 )          
    1      0    SORT (AGGREGATE)                                                    
    2      1      TABLE ACCESS (FULL) OF 'STAT' (Cost= 169  Card= 900001  Byte          
          s= 9000010 )                                                            
                                                                                
Statistics
----------------------------------------------------------                      
        2753   consistent gets                                                    

SQL> select /*+ RULE */ max(j) from stat where i<= 900000 ;

Execution Plan
----------------------------------------------------------                      
    0       SELECT STATEMENT Optimizer=HINT: RULE                                 
    1      0    SORT (AGGREGATE)                                                    
    2      1      TABLE ACCESS (BY INDEX ROWID) OF 'STAT'                           
    3      2        INDEX (RANGE SCAN) OF 'STAT_I' (NON-UNIQUE)                     

Statistics
----------------------------------------------------------                      
        4477   consistent gets