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+

    O

    33

           A

         29

       B

      12

        AB

       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

Probability that a random selection is both group B and type Rh+ =(12/114) = 2/19

For replacement case:

the probability that that 2 selected subjects are both group B and type Rh+ = 2/19 * 2/19 = 4/361= 0.01108

For without replacement case:
the probability that that 2 selected subjects are both group B and type Rh+ = (12/114)*(11/113)= 2/19 * 11/113= 22/2147=0.010247