# Mean of a tree diagram

• November 19th 2011, 08:07 AM
Mean of a tree diagram
What is the equation for finding E(S2)

Thanks

http://i41.tinypic.com/2czc6x5.png
• November 19th 2011, 08:43 AM
Plato
Re: Mean of a tree diagram
$E(S_2)=1\cdot \mathcal{P}(1)+6\cdot \mathcal{P}(6)+9\cdot \mathcal{P}(9)$
• November 20th 2011, 02:51 AM
Re: Mean of a tree diagram
Quote:

Originally Posted by Plato
$E(S_2)=1\cdot \mathcal{P}(1)+6\cdot \mathcal{P}(6)+9\cdot \mathcal{P}(9)$

Is P(1) just 1/5 x 2/3???
• November 20th 2011, 03:10 AM
Plato
Re: Mean of a tree diagram
Quote: