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Re: A question on conditional probability!
Posted:
May 26, 2006 8:16 PM


Sticker wrote: > I have a question, how to calculate the probability as following: > P(A1 & A2 & A3  B)? > Given the condition that event B happens, how to calculate the > probability of all A1, A2 and A3 happen? Here A1, A2, A3 are > independent with each other but they are dependent with B separately. > > Can I say: > > P(A1 & A2 & A3  B) = P(A1  B) * P(A2  B) * P(A3  B)?
In general, no. Marginal independence does not imply conditional independence. Look up "Simpson's paradox".



