Birthdays in the USA

- [Instructor] Back in elementary school,…birthdays were important.…I mean, really important.…It's your special day.…A day where the class is focused on you.…Somehow, there always seemed to be a couple of kids…that shared a birthday.…The horror.…What kid wants to share their special day with someone else?…Two out of only 30 students.…What are the chances?…15%.…No.…Must be lower.…365 days in a year.…

30 kids in a class.…It must be about 10%.…Welp, believe it or not.…The odds of having two identical birthdays…in a room of 30 people,…it's about 71%.…And this assumes all birthday are equally likely.…They aren't though.…Some days are very popular.…Others are not.…Based on data collected in the U.S. between 1994 and 2014,…the most popular birthday is September ninth.…

Actually, many of the most popular birthdays…are in the month of September.…Why?…Well, it seems Americans make babies…when they have extra time.…Vacation time.…The holidays.…Give lots of Americans lots of time off…in late December and early January,…and chances are that nine months later,…