Originally Posted by

**Archie Meade** I guess you could say each birthdate is equally likely,

though they are not, since the probability of being born on Feb29

is a quarter the probability of being born on any other date, if we disconsider seasonal conception bias.

If we have n people in a room (classroom), all born in the same leap year,

then we can use that approximation.

In that case it is simplest to find the probability that less than 2 people have an April 1 birthday.

The probability that __no-one__ has an April 1 birthday is $\displaystyle \left(\frac{365}{366}\right)^n$