Common Birth Dates asked for the expected number of pairs of common birth dates for a cohort of 1000 people whose ages were clustered around a certain value.

Now consider a similar question to the traditional birthday problem: If you attend a concert or other event where people tend to be of a similar age, how large would such an event need to be in terms of number of attendees, so that you'd have at least a 50% probability that there would be at least two people born on the exact same day (year, month and day)?

Again to make things specific: assume the standard deviation about whatever the mean age to be is 12 years and it follows a normal distribution.

Again feel free to vary the assumptions about the distribution.

(A) When the event is attended by 147 people, the probability of finding at least two people born on the same day is almost exactly 50%.

Posted by K Sengupta on 2022-05-11 21:56:15