Using Cursor For Update Statement?

I would like to get the results of a cursor into update statement but it fills only the last record of the cursor

this is the cursor:

Code:
DECLARE @avg varchar(50)
DECLARE @cur_avg CURSOR
SET @cur_avg = CURSOR FOR
select cast(avg(cast(reply as decimal(12,2))) as decimal(12,2)) from tbl_app_monitoring
group by test_name, application_id

this is the update statement:

Code:
OPEN @cur_avg
FETCH @cur_avg INTO @avg
WHILE (@@FETCH_STATUS = 0) BEGIN
UPDATE tbl_app_monitoring_archive
SET average = @avg
FETCH @cur_avg INTO @avg
END

is it also possible to do this without the cursor ?