birth month!

you probably know we try to eek as much celebration out of birthdays in our house (without being ridiculous, obviously). we celebrate a birth MONTH and james' birth month has arrived. he will turn 6 in a few days, he will have a birthday party in the place he's been begging to go (chuck e. cheese), and he will get to be the special friend in his classroom. this is all a pretty big deal for a little tiny 5 year old.


i was thinking about the special friend thing. there are 23 kids in his class. there are 365 days in a year. yet, over the past few years, in one or both of my kids' classrooms, there have been 2 kids with the same birthday. it seems unlikely, given that few of data points (23) and that many possibilities (365). but it is explained by the birthday paradox, which i spent some time this weekend trying to understand while listening to this VERY EXCELLENT episode of this american life. i've now been thinking about it since, for a few days and counting....which is probably why i forgot to change the clocks on sunday morning, which lead to an awkard moment at church on sunday... anyway, it seems like you need a minimum of 23 people to achieve the odds of 50-50 that there will be at least one match in the room. that. is. crazy. click that link there for a great explanation.


side note: if you have an hour, and are a curious person, and sometimes wonder "how do i know what i know?" then given this a listen. it is wonderful:
https://www.thisamericanlife.org/radio-archives/episode/630/things-i-mean-to-know
if you only have  a few minutes and wonder about this birthday paradox, go to the section about voter fraud. trust me: it's worth it.


with all that said, there isn't another november 17 birthday in his classroom this year, but there is another james with a mother named marta, and that one blows my mind.