Blood types:The blood type O negative is called the "universal donor" 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

22

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 .

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 .

A binomial experiment has the given number of trials

n

and the given success probability

p

.

=n15

,

=p0.2

Part 1 of 3

(a)Determine the probability

P1orfewer

.Round the answer to at least three decimal places.

P1orfewer =

Part 2 of 3

(b)Find the mean. Round the answer to two decimal places.

The mean is .

Part:2 / 3

2 of 3 Parts Complete

Part 3 of 3

(c)Find the variance and standard deviation. Round the variance to two decimal places and standard deviation to at least three decimal places.

Thevarianceis. Thestandarddeviationis.