HELP writing an Excel IF statement

Hello,

I have one cell (I122) that displays the sum of a range. I'd like to change the value of cell "X" if the sum falls between value a or b. If the sum falls between c or d, I'd like value of cell"X" to display another number, etc...

Here's what I have so far (not working):

=IF(AND(i122>0,i122<99999),.15),(AND(i122>=100000,i122<174999),.16),(AND(i122>=175000,i122<249999),.17),(and(i122>249000),.18))))

Once I have a working formula, I need to make sure the cell reference to I122 remains static as I plan to copy the formula down the column.

Help PLEASE!?