Interest rates are floated in Qatar. It is up to each individual bank to decide how much to pay you on your deposit. So, it is the bargaining power of the individual or company opening the account vis-a-vis the bank's representative employee or branch manager; the value of your deposit; the type of account being opened and the length of time period you will hold your money with the bank without any withdrawal or the term of the deposit.
In breif, you have to shop around and bargain with them for the best rate of interest that you can get.
Good luck.