Your biggest issue is that Campbell U is not a well-known institution, so it will be difficult for admissions committees to assess what those 'A's really mean. If possible, try to get letter writers who have held positions at better-known institutions and encourage them to comment on how you stack up against students at those places (assuming it's favorably). Previous posters' advice to the contrary, don't worry too much about your GRE scores (they're fine) or statement of purpose (it won't make or break your application).
I think you're facing an uphill battle for PhD admission at NC State, UNC, and Duke. I don't have as much of a feel for where you'd stand at those other places, but apart from South Carolina none of them has much of a reputation in statistics. If your eventual aim is a PhD at a top-tier school (like the Big Three NC schools), you might be well-served to apply to some good Masters programs, and build your profile from there. Masters programs are a lot easier to get into, and strong performance in one that's well-regarded will be a major asset when applying to a PhD program.