I want to make a birthday party with 50% chance that at least two people will have the same birthday date, what is the minimal number of people I will have to invite? Supposing we do not count leap years and that I have to invite at least 2 people.

Question

mtblue7 · Answer

4?

zootedyoungin · Answer

Hm

p0sitr0n · Answer

If we assume that each day of the year has an equal probability to have a child born during it (uniform distribution), then 23 https://en.wikipedia.org/wiki/Birthday_problem

mtblue7 · Answer

oh

p0sitr0n · Answer

The table there shows P(two people do not have the same birthday), so 1-that should give you your answer.

_malice_ · Answer

You are correct P0sitr0n, thanks.