Hennofletch said:
For there to be a 100% chance two people share the same birthday there must be 366 people.
A 99% chance is reached by 57 people and a 50% chance by just 23.
This is not true. First of all, there can't be a 100% chance. If you pick 366 random people, you can still be statistically unlucky to not have the same birthday. Heck, even if you pick 3000 random people you still have no guarantee. Even though it is statically unlikely, you never get a 100% chance.
Not sure about the following, but if you say you have a 99% chance you share the same birthday with 57 random people, then you are saying the other 308 days fall within the 1% margin, meaning about 80% off all people have a birthday within the same 57 days of the year. That is just... weird.