# Probablity Problem

• Oct 28th 2012, 10:14 PM
vmd
Probablity Problem
If E is independent of F , F is independent of G and further E is independent of FG, then prove or disprove G is independent of EF?(Headbang)
• Oct 28th 2012, 10:29 PM
chiro
Re: Probablity Problem
Hey vmd.

Hint: Use P(A and B) = P(A)P(B) and consider a case where A (in this example) corresponds to two events like P(A) = P(C and D) = P(C)P(D)
• Oct 28th 2012, 10:31 PM
vmd
Re: Probablity Problem
Can you be more specific because I didnt understand what you are trying to say.
• Oct 28th 2012, 10:32 PM
chiro
Re: Probablity Problem
If G is independent to EF then P(G and EF) = P(G)P(EF).
• Oct 28th 2012, 10:37 PM
vmd
Re: Probablity Problem
Thats true,but how could i prove that ???
• Oct 28th 2012, 10:45 PM
chiro
Re: Probablity Problem
Thats the definition of independent: If two events A and B are independent then P(A and B) = P(A)P(B).

You can think of this as P(A|B) = P(A) where B doesn't affect the outcome of A at all (i.e. they really are independent) and the definition of P(A|B) = P(A and B)/P(B) = P(A) which means that P(A and B) = P(A)*P(B). That's the intuitive reason why you have independence in mathematical form.