692
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 02 May 2024
692 points (96.0% liked)
Showerthoughts
29239 readers
1334 users here now
A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.
Rules
- All posts must be showerthoughts
- The entire showerthought must be in the title
- Posts must be original/unique
- Be good to others - no bigotry - including racism, sexism, ableism, homophobia, transphobia, or xenophobia
- Adhere to Lemmy's Code of Conduct
founded 1 year ago
MODERATORS
The probability of 2 people having the same birthday is 1 in 365 because it's the same as picking person A's birthday as a specific day in the year and checking whether person B has their birthday on that date.
Now, the reason the number is so low is that you are basically comparing pairs and with 23 people there are 253 different pairings (23 choose 2 or
22*23/2). With each pair having a 1/365 chance to have the same birthday and having 253 distinct pairs, you would have to fail a 1/365 check 253 times in a row. The formula you can use for the success rate is1 - (1-p)^xwith p being the probability and x the number of trials, so in this case1 - (1 - 1/365)^253 = 0.5004In essence, the unintuitive part of the "paradox" is how fast the number of possible pairs grows the more people you add.