# 2D table of random variables

• Apr 19th 2012, 08:13 AM
Nforce
2D table of random variables
We have two random variables.

Attachment 23650

Attachment 23651

I would like to know how to get the probabilities p1, p2, p3 ... of two random variable in a table?

Attachment 23652

I just know that the sum of all probabilites p1, p2, p3... must be equal to 1!
• Apr 19th 2012, 08:51 AM
Plato
Re: 2D table of random variables
Quote:

Originally Posted by Nforce
We have two random variables.
Attachment 23650
Attachment 23651
I would like to know how to get the probabilities p1, p2, p3 ... of two random variable in a table?
Attachment 23652
I just know that the sum of all probabilites p1, p2, p3... must be equal to 1!

Just let $m=1,~2,~3~\&~n=1,~2,~3$ form a matrix $J=\left(a_{m,n}\right)$ where $a_{m,n}=P(x_m)\cdot P(y_n)$.
• Apr 19th 2012, 09:21 AM
Nforce
Re: 2D table of random variables
Thank you, the sum is really 1. Can I ask is this a general rule? Is correlation or dependence effect this?