Probability there are four basic blood groups: o, a, b, and ab. ordinarily, anyone can receive the blood of a donor from their own group. also, anyone can receive the blood of a donor from the o group, and any of these four types can be used by a recipient from the ab group. all of the other possibilities are undesirable. an experiment consists of drawing a pint of blood and determining its type for each of the next two donors who enter a blood bank.