this post was submitted on 28 Feb 2026
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Can you explain the math?
Adding one more person adds more than one comparison. Assuming birthdays are evenly distributed (they aren't), 2 people have a 1/365.25 chance of sharing a birthday. But adding a third person adds 2 more chances. Adding that 23rd person adds 22 more chances than adding the 22nd person. 1+2+3...+22=253 separate checks, of which only one needs to match.
So does this apply to the problem: 0.6% of people have micropenis. How many friends do you need to have before you’ll know someone?
It doesn’t seem to, because there isn’t any element of comparing them between each other. It’s just a straight percentage chance.
Maybe is you ask the question like this:
If a person with a micropenis is in a room, how many men are needed in that room to have a 50% chance of someone else in there also with a micropenis? And how many women in that room are needed for a 50% chance a woman has a bigger clitoris than that person's micropenis?
Or:
How many men in a room are needed to have a 50% chance someone else has the same penis size?
Yeah that would turn it into more of a birthday problem.
It would also make it downright weird.
So you mean a room full of men talking about their size, or a full scale measuring contest?
Both would be fucking weird though xD
No I was making a joke and everyone decided they were gonna do a full autism about it
Ok boomer, maybe it's time for a little nap. What's wrong with my autism?
Wiki Birthday Problem
I think the point is not how quickly can someone Google it but can he actually explain it, because he brought it up in a situation where it doesn’t apply, meaning he doesn’t actually understand it (ie can’t explain it).
Canconda’s original comment did not have the wiki link which is why I replied. Honestly, dropping 23 possible birthday pairs to reach >50% probability is still not intuitive to me.
Of my OG friend group of ~12 there are two matching birthday pairs. One coincidental and one pair of twins which don’t count.
To grasp it intuitively, I think of it like this.
With the first person, you have 1/365 chance the birthday will be on any given day.
Each person you add to that adds not just another person but also another day that can be a match.
After two people, you still don’t have a match but now you have two days. The third person can match either of those. That’s a lower bar than person #2 had to meet.
By the time the 15th person walks in, the question is: “what are the odds that you share any of these 15 days as your birthday.” And remember, it’s not that that person’s odds are 50%. It’s everything from the original 1/365 chance on up to that fifteenth person, cumulatively, that has a 50% change of a hit.
See how this already sounds a little more likely than just narrowing in on the final final result of two people having the same birthday? The way the problem is phrased makes it sounds like more of a bullseye than it truly is.
So I think part of it is just difficult to grasp intuitively, but it’s also phrased deliberately to throw off your intuition.
I can see it kinda. At the same time you are reducing the unique dates and increasing the people you could match with.
I can't because probability is bullshit lol.
Damn you guys have no sense of humour.
If that was your idea of a joke, I’m afraid you have no idea what’s funny. More likely you are just attempting to laugh off your embarrassment.
Buddy if you tell jokes to make other people laugh... sorry that sucks. Wouldn't' wish that on my worst enemy.
I'm lmao and y'all are shitting bricks about math
You suck at math and we are lmao at your attempts to hide it.
THATS THE JOKE!!!!!!!!!!!!!!
you daft ass mf
Chill, bro, I’m just joking!
https://en.wikipedia.org/wiki/Birthday_problem
Very easy to google ngl.