I was noticing last night that of my 400 Facebook friends, 5 of them have a birthday on Thursday. That’s not including the ones that are businesses with a “start date” of the end of the year or friends who do not allow access to their birthday. I mentioned to my husband that it was improbable. With 365 days in a year, I should only have one birthday friend per day–two tops. He started talking about the “birthday paradox” and how if you put only 23 people in a room, you would have 2 people with the same birthday. I thought he was nuts. I mean, 365 days? Out of 23 people 2 will have the same birthday?
So of course I did a search for it. I found the “Birthday Problem” Wikipedia page, which explains that if you have 23 people together, there is a 50% chance that 2 of them will have the same birthday. If you get 57 people, there is a 99% chance that 2 of them will have the same birthday. It still doesn’t seem possible. 366 possible birthdays. 57 people and you have a 99% chance of the same birthday popping up?
Here is where YOU come in. I need a little help from my social media friends because I can’t get 23 or 57 people into a room today. Can you leave a comment below with your name and your birthday? I don’t need the year. Leave your name so I can verify you’re real people when two birthdays pop up the same and it isn’t just someone messing with me. I’ll make a little chart and we’ll see how many people have to comment before we get the same birthday. Curiosity has gotten the best of me now!!
Edited: It took only 18 people posting to get our first repeat birthday. We defied the odds! And my husband proved, once again, that he is better at math than I am.