Question 998977: Im very confused by the questions in this problem.
Heres the table i am being given
Refer to the table below. Given that 2 of the 300 subjects are randomly selected
GROUP
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(type)O A B AB
Rh+ 95 97 38 17
Rh- 25 16 8 4
i hope this table can be read correctly
a. Assume that the selections are made with replacement. What is the probability that 2 selected subjects are both group A and type Rh+?
b. Now assume the selections are made without replacement. This means the probability of selecting the second subject who is group A and Rh+ is not the same as the probability of selecting the first subject?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! With replacement, multiply the probabilities.
type)O A B AB
Rh+ 95 97 38 17 =247
Rh- 25 16 8 4 ;;;;=53
;;;;120/113/46/21=300
A+ is 97/300
With replacement the probability of 2 is (97/300)^2=0.1045
Without replacement, the probability is (97/300)*(96/299)=0.1038
The numerator and the denominator both decrease 1, and because of the relatively large sample, the change in probability is not much. It is lower, and it should be with one less A+ to choose from.
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