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The Birthday Paradox Experiment (2018)

pudding.cool

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Re: The Birthday Paradox Experiment (2018)

#12

Post by senectus1 »

kibibu wrote: post #4
bsimpson wrote: post #3

It's interesting how uniform the birthday distribution at the end looks. I'd expect more seasonality (e.g. more babies conceived in the cold, dark months).

Weird how, coincidentally, 3x as many people are born on Nov 15 as any other day

is that US Nov 15th?

Cause I was born in Australia on Nov 14th :-D

Re: The Birthday Paradox Experiment (2018)

#13

Post by ropejumper »

kqr wrote: post #7
bsimpson wrote: post #3

It's interesting how uniform the birthday distribution at the end looks. I'd expect more seasonality (e.g. more babies conceived in the cold, dark months).

Remember that the seasons are inverted on the other side of the equator. (Granted, the population splits something like 90/10 but still.)

There are relatively few people living south enough to have "cold and dark winters," anyway. The northern hemisphere is much more concentrated towards the north.

Most people live above 35°S where, at the most extreme, winter days are about 10 hours and a half long (plus about an hour of decent twilight). Temperatures obviously vary depending on region but they don't really get much below 10°C as far as I know.

So really, it's more like mostly bright and somewhat chilly.

Re: The Birthday Paradox Experiment (2018)

#15

Post by zeristor »

phito wrote: post #8

I really like the fact that it's using the previous user birthdays. Unfortunately today is my birthday and I think a lot of people are entering today's date as their birthday, I got 6 matches... :)

Nothing unfortunate about having a birthday today.

Happy Birthday!

Re: The Birthday Paradox Experiment (2018)

#17

Post by bambax »

bsimpson wrote: post #3

It's interesting how uniform the birthday distribution at the end looks. I'd expect more seasonality (e.g. more babies conceived in the cold, dark months).

Yes, it's also extremely unlikely.

The actual distribution in developed countries is not uniform: there is a spike at the end of September (because many more people make babies at or around New Year's Eve) and a considerable drop on Dec. 25th (because people will avoid that date and provoque the birth some days before in case it might happen).

Also, on the site there is a huge spike on Nov. 15 which, incidentally, is the birthday of the author: maybe they tested it many times?

Re: The Birthday Paradox Experiment (2018)

#20

Post by dvt »

nuancebydefault wrote: post #16

I'm a bit confused. Maybe i did not pay enough attention but... Does it stop the first simulation when there are _any_ 2 people with a same birthday, or when someone has _my_ birthday? I think the latter will take more people on average.

The website is being purposefully obtuse and the birthday paradox is a "paradox" because it's sometimes formulated in the same way as the website. In other words, you are completely correct that the intersection of any two birthdays is significantly more likely than the intersection of a particular birthday.
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