A full standing prime rib is 7 ribs, about 15 pounds, and large enough to feed up to 14 people. Prime rib is “standing” when the bones are included in the roast, allowing the roast to stand by itself. It’s important to keep in mind that just because you have “prime” rib, it doesn’t mean that it’s USDA Prime. Most of the time the “prime” ribs we get at the grocery store is actually USDA Choice quality – which is fine,...