So that I may better navigate my way around my new home, I have been taking French classes.
However, this post is not to pontificate on the difficulties of learning a new language or to gripe over how difficult I find it to pronounce certain French words. Oh, not to mention the whole conjugating thing.
Instead, this post was to mention something I found rather intriguing. There are only nine (there’s your number for the day) students in our class and as we went around the room introducing ourselves we also were asked to say our birthdays.
As it turned out, two people in our ennead had the same birthday.
What are the odds of that?
Well, it turns out, I could figure out what the odds were. The puzzle of figuring out what is the probability of n people sharing the same birthday is known as the birthday problem.
According to the graphic in the Wikipedia article that I have linked to, the odds of nine people sharing the same birthday is less than 10 percent.
This web page shows how to calculate the odds of a group of n people not having the same birthday.
For the computer programmer in your house, this page shows you how to write a program to calculate the probability.
For me, the thing I wanted to know was if our pair of conjoined birthday celebraters felt ripped off. Because both people shared December 24th as their birthday, did they only receive one set of gifts?