Blood types: The blood type O negative is called the "universal donor" type, because it is the only blood type that may safely be transfused into any person.
Therefore, when someone needs a transfusion in an emergency and their blood type cannot be determined, they are given type O negative blood. For this
reason, donors with this blood type are crucial to blood banks. Unfortunately, this blood type is fairly rare; according to the Red Cross, only 7% of U.S. residents
have type O negative blood. Assume that a blood bank has recruited 19 donors. Round the answers to four decimal places.
a) what is the probability that three or more of them have type O negative blood?
b) what is the probability that fewer than four of them have type O negative blood?
c) It (would/wouldn’t) be unusual if none of the donors had type O negative blood since the probability is __?