I missed part of my last stats class and don't understand the homework at all so I was hoping someone here could help me understand it...
The question is on blood groups and Rh types of 100 subjects and table shows this..
O A B AB
Rh+ 39 35 8 4
Rh- 6 5 2 1
And the question is:
If 3 of the 100 subjects are randomly selected, find the probability that they are all group B and type Rh-.
a) Assume that the selections are made with replacement.
b) Assume that the selections are made without replacement.
So I know that with replacement the sample size doesn't change but without replacement it decreases, but that is all i know for setting up this problem.
I appreciate any help I can get! Thanks!