Thread: Probability Fun
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Old 06-10-2010, 02:28 AM   #11
pdurrant
The Grand Mouse 高貴的老鼠
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Quote:
Originally Posted by beppe View Post
Without any information we have

2B = 0.25
BG+GB= 0.5
GG=0.25
(the second is independent from the first one so we can add)

with the knowlege that one at least is a boy
we have to take away GG and renormalize to 1 so I divide for =.75. This gets
BB=1/3
BG+GB =2/3
GG=0

Tuesday has nothing to do with it (it would have been like asking is one of your boys left handed? or with blue eyes, or sleeps at night?)
so the probabilities remain the same.
Your analysis of the first two probabilities is spot on. But you've missed something for the third.
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