Actual Table size

I have used below query to calculate table size.

SELECT  Segment_name, Segment_type, Bytes, (Bytes/ 1024)/ 1024 Mb

  FROM  Dba_segments

WHERE  Segment_type = 'TABLE'

    AND Segment_name in ( 'TABLE');

O/P: Bytes: 1441792

Size in MB: 1.375

So, I have deleted a few records from my table and re-queried. But nothing is changed I got same result.

Usually, after deleting the records the table size should be reduced correct but i did not happen.