Refer to the table below given that 2 of the 114 subjects ar

Refer to the table below given that 2 of the 114 subjects are randomly selected

Rh+

    33

         29

      12

       12

Rh-

     11

           9

         4

      4

GROUP       O                                                 A                                    B                               AB

Rh+                              33                                              29                                 12                               12

Rh-                                11                                               9                                  4                                 4

Assumed that a selection is made with replacement. What are the probability that that 2 selected subjects are both group B and type Rh+?

Assumed that a selection is made without replacement. What are the probability that that 2 selected subjects are both group B and type Rh+?

Solution

Group
O A B AB
Type Rh+ 33 29 12 12
Rh- 11 9 4 4
If 2 of the 100 subjects randomly selected
the probability that they are both group O and
type Rh+.
P(a person is O and type Rh+) = 33/100
-------
a.assume the selections are made with replacement
P(2 people are O and Rh+) = 0.33^2 = 0.1521
------------------
b.assume the selections are made without replacement.
(2 people are O and Rh+) = (33/100)(32/99) = 0.1497

People with blood O and type Rh- are considered
to be universal donors, because they can give
blood to anyone If 4 of the 100 subjects

are randomly selected, find the probability that
they are all universal donors.
a. assume that the selections are made with replacement.
0.33^4

b. assume that the selections are made without replacement.
33C4/100C4 = 0.0210