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by dwighttk 666 days ago
That seems to be saying it is extremely likely that the only other person in my zip code that shares my birthdate is opposite gender
3 comments
alwa 666 days ago
Only 50% of the time, but that’s 50% better of a guess than you’d make without knowing gender.

ZIP codes contain maybe 40K residents [0] (many contain fewer) and there have been around 25K days in the last 70 years. Sure births are not evenly distributed, but still...

[0] https://www.unitedstateszipcodes.org/images/comparison-of-po...

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aftbit 666 days ago
That sounds like a pitch for one of those "singles near you" apps. Find hot women in your area who share your birthdate!
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paulmd 666 days ago
statistically, 50% chance, innit?
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dwighttk 666 days ago
OP seems to claim 13% same / 87% opposite
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jsnell 666 days ago
I don't think you can make that conclusion.

I think you're making the assumption that all three data points are needed for all 87%. But obviously some people can be uniquely identified based on just {zip, date or birth}, such that gender isn't necessary.

So the distribution could e.g. be 8% same, 8% opposite, 5% both, 79% neither, and explain the original numbers without triggering the paradox.

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dwighttk 665 days ago
Yeah I was off, but by their numbers

87% of the time, there are no others on my birthdate or there is one other and opposite gender.

13% of the time is 1 same gender or more of either or both.

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