Chapter 8.7, Problem 85PE

The blood type of an individual is classified according to the presence of certain antigens, substances that cause the immune system to produce antibodies. These antigens are denoted by A, 8, and Rh. If an individual's blood contains either the A or B antigen, these letters are listed in the blood type. If neither A nor B is present, then the teller 0 is used. U the Rh antigen is present, the blood is said to be Rh positive (Rh+): otherwise, the blood is Rh negative (Rh^-). Under this system, a person with AB+ blood has all three antigens, and group O^- is absent all three antigens.

The distribution of blood types for people living in the United States is given in the table. (Source: Stanford School of Medicine, http://bloodcenter.stanford.edu) Refer to the table for Exercises 75-82. Round to 3 decimal places when necessary.

Type	Probability
${\text{O}}^{\text{+}}$	0.374
${\text{O}}^{-}$	0.066
${\text{A}}^{+}$	0.357
${\text{A}}^{-}$	0.063
${\text{B}}^{+}$	0.085
${\text{AB}}^{+}$	0.034
${\text{AB}}^{-}$	0.006

a. If an individual is randomly selected from the population. find the probability that the individual will have the Rh factor.

b. If three people are selected are random, find the probability that they all have the Rh factor.