I am working on a statistic problem. I define "A" as the number of all the products in the warehouse, but some of the products are not qualified and I need another parameter to describe the number of the qualified products, for example, "B". Then, what should I say about B? Could I say that B is the number of all the products except for the unqualified ones? Is "except for" a proper expression? May I have other words or phrases that fit the situation better? Thanks a lot!
Try using 'A' as all products in the warehouse and 'B' as all qualified products in the warehouse.
If instead we use an exclusion method, such as 'B' as all products in the warehouse excluding all unqualified products, it suggests that 'B' contains products that are qualified plus products that have not yet been processed to a qualified or unqualified state.