Question

About 1/4 of all adults in the United States have type O+ blood. If four randomly selected adults donate blood, find the probability of each of the following events. (Enter your answers as fractions.)
(a) All four are type O+.


(b) None of them is type O+.


(c) Two out of the four are type O+.

Answer 1

let A be the event that adults have blood type O
a)P(A)=1
B)P(A')=1-P(A)=0
c)P(2/4)=1-0.5=0.5