selct max row from a table

Question

i have a table which include fields, subjectname,title,status,marks
a subjectname can have more than one row with different marks , i have to select row with maximum marks.
for example
i have 5 rows with record.

subjectname | title| marks|status

maths | basic| 66|paid
maths | basic| 89|not paid
maths | basic | 73|paid
computer | basic | 39|paid
computer | basic | 78|paid


the result i need is
maths | basic| 89
computer|basic |78

i used
SELECT  subjectName, MAX(Marks) AS Expr1
FROM  OnlineTestResults
that is

maths | 89
computer|78

it ives required result but when i use

SELECT Status, TestName, MAX(Marks) AS Expr1
FROM  OnlineTestResults
it give wrong result as
maths | 89|Not Paid
maths|73|paid
computer|78

can any one help me??????