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Old 07-17-2007   #1
Alexander
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Default If you count people passing by you, and first 100 are all men, what is...

...probability that 101th would be woman? Snoy:If a father has 100 sons in a row,then almost certainly there is somethingwith his DNA that makes female fetusesalmost unviable.
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Old 07-17-2007   #2
morningfoxnorth
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You are at a men's club. The probability that the next person is a man is at least 98%.
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Old 07-17-2007   #3
marvin0258
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The probability is the same on matter how many men you counted, it could be ten thousand. There is a 50% the next person you walk by is a woman. (Unless your in some space completely dominated by men) But assuming that your in an open space with the population relatively half men half women the probability is 50%. Just because the first 100 are men doesn't mean the 101st with be a man. Likewise just because you've seen a hundred men walk by you doesn't mean that then 101st must be a woman.
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Old 07-17-2007   #4
pki15
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50%, the first 100 events are independent of the last event.
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Old 07-17-2007   #5
heidegger_001
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I think probably about 50 percent because 100 is small number compared to 6 billion people in the world. I'm not sure about the ratio of men to women though.
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Old 07-17-2007   #6
chipmunkian
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Assuming that men and women are 50/50, then the odds would be 1-in-2. The odds do not change for each individual event regardless of what has happened before,
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Old 07-17-2007   #7
Lobster
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It is definitely not 50%. The odds of 100 men passing by you with 50% odds is 2^100 and that is too much of a long shot to dismiss as chance. There is no way to tell the exact odds without more details but I would estimate a 1% chance of seeing a woman.
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Old 07-17-2007   #8
Snoy
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Actually, the probability is indeed 50%. The question does not say "passing by you at a men's club". And similarly, if you have (however unlikely) 100 children, and they are all male, the probability that the 101st child is a female is STILL 50%.There are two options, male or female. Always 50% in generic cases such as this one.
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Old 07-17-2007   #9
bretty418
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Depends where you are.In Saudi Arabia, a woman can't go out alone.So it's all relative.
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Old 07-17-2007   #10
Dr D
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If you say the answer is anything other than 1/2, it's because you are making up details as you go along.Some answerers above say that if they see 100 men, then it's a strong indication that a lot of men are present. Another person would say that if they see 100 men pass by, there can't be too many left. Without details, the answer is 1/2.RE: Lobster's answer.I agree that if 100 men pass by in a row, the prob of that = 0.5^100. But if 50 men and 50 women pass by in an alternating fashion (M-W-M-W...), the prob of that is also 0.5^100.
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