nesting

[Dan]

I created a calc field in my query that gives me a sum of
2 fields called "BedTotal:" yielded a number between
15,000 and 1500. Based on the "BedToals:" output I wanted
to create new calculated field called "EffFactor:" with a
nested IIF whereas EffFactor:IIF([BedTotal]>=10k,"1.1",
[BedTotal]>=5000,"1.05", greater 3.5k...2k and so on...
Using IIF statement I have too many arguments. Is there
another way to nest the IFF or use the Btween.And? Thanks.
Dan