I need help find tuning my science fair question. HELP?

I’ve done my test on the radioactivity levels in granite countertops used in peoples’ homes. The general question i have in mind is “What is the range of radioactivity levels in granite counter tops and are the levels high enough to effect a person?” but lets all admit, that sounds pretty bad. Any ideas? I can tweak the wording as much as a want, but I can only redirect the question a tiny bit. I need to know as quickly as possible; my sciene teacher expects me to know by tomarrow for a GRADE and a big one too!