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 21 donors. Part 1 of 2 (a) What is the mean number of donors who have type O negative blood? Round the answer to two decimal places. The mean number of donors who have type O negative blood is X Part 2 of 2 (b) What is the standard deviation of the number of donors who have type O negative blood? Round the answer to four decimal places. The standard deviation of the number of donors who have type O negative blood is X Check Save For Later Submit Assignment LC. All Rights Reserve Terms of Use | Privacy Center | Accessibility