# Statistics help, probability tree diagram

1. Apr 5, 2009

### tweety1234

1. The problem statement, all variables and given/known data

Please can someone help me with this question, I am really stuck. I have drawn a tree diagram but I dont think it is correct, as it does not give the right answer. Can someone have a look at it and show me were I have gone wrong? Or show me what the tree diagram should look like.

from my tree diagram I get the answer for questions 'c'

($$\frac{6}{10} \times \frac{5}{9} \times \frac{4}{8}$$ )+ ( $$\frac{6}{10} \times \frac{4}{9} \times \frac{5}{8}$$) + ($$\frac{6}{10} \times \frac{5}{9} \times \frac{4}{8}$$ ) + ($$\frac{4}{10} \times \frac{6}{9} \times \frac{5}{8}$$ )

thank you!

btw- 'E'- stands for elimnated
NE- stands for not elminated.

http://www.mathhelpforum.com/math-help/attachments/basic-statistics-probability/10795d1238940269-tree-diagram-probability-untitled.jpg [Broken]

Last edited by a moderator: May 4, 2017
2. Apr 5, 2009

### cristo

Staff Emeritus
You seem to be summing up too many branches. Look back at your tree: instead of saying 'E and NE' it should be 'female eliminated and male eliminated' (to make things clearer). Then, which branch is the one that gives the probability of 'given the first elimination is male, what is the probability the second two are both female'?

3. Apr 5, 2009

### tweety1234

But since its 3 rounds, than should it not be 3 branches? I will re-draw my diagram and post it up.

thank you.