1)

The American Red Cross reports that 12% of Americans have blood type B. Nassau

County had a blood drive recently.

a)

How many blood donors should the American Red Cross expect to collect from until it gets a

donor with blood Type B?

b)

What is the probability that the twelfth blood donor is the first donor with Type B blood?

c)

What is the probability that exactly 2 of the first 20 blood donors have type B blood?

d)

What is the probability that at least 2 of the first 10 blood donors has type B blood?

e)

The blood drive has a total of 2050 donors. Assuming this is a typical number of donors

for the county, what would be the mean and standard deviation of the number of donors who have Type B

blood?