Thank u soooo much to all those that wished me a Happy Birthday.I truly am blessed by having such great fans people in my life!
— Misty May-Treanor (@MistyMayTreanor) July 31, 2012
There’s one song being played at the XXX London Olympics more than any other ditty — more than the anthem’s of gold-medal leaders China and the United States combined.
It’s the traditional celebratory jingle “Happy birthday.”
There are 32 Olympic athletes — from USA’s Tia Brooks to Poland’s Lukasz Zygadlo — who will go out to dinner tonight and pray their teammates don’t employ the waiters to sing for them.
It’s called the Birthday Paradox, although it’s more of a mathematics equation than an absurd coincidence.
You don’t have to be Neil Degrasse Tyson to figure out the odds of someone sharing a birthday in a sample size of 10,960 athletes from 205 countries.
In fact, all you need is a pool of 75 athletes for a 99.9 percent chance that two of them will end up running around the Olympic Village in their birthday uniforms.
(Although, it sounds like just about everyone runs around the Olympic Village in their birthday suits at night).
A sample size of 75 competitors is nothing. There are twice that many athletes and coaches (158 total) on Team USA’s track & field team alone.
Even with as little as 23 people, the odds of a birthday match are 50-50.
You only need a dozen players from Team USA’s women’s basketball squad to find a match. Maya Moore and Diana Taurasi were born seven years apart on June 11.
According to BetterExplained.com:
With 23 people we have 253 pairs:
23 X 22 / 2 = 253
The chance of 2 people having different birthdays is:
1 – 1/365 = 364/365 = .997260
Makes sense, right? There’s 364 out of 365 birthdays that are “OK.”
Having all 253 pairs be different is like getting heads 253 times in a row (well, sort-of: let’s assume birthdays are independent). We use exponents to find the probability:
(364/365) 253 = .4995
99.7260% is really close to one, but when you multiply it by itself a few hundred times, it shrinks. Really fast.
The chance that we have a match is: 1 – 49.95% = 50.05%, or just over half! If you want to find the probability of a match for any number of people n the formula is:
P(n) = 1 – (364/365) c(n,2) = 1 – (364/365) n(n-1)/2
Honestly, for a math dolt such as myself, that doesn’t better explain anything for me. Simply dividing 10,960 by 365 gives us 30 people — a simple, yet likely flawed, equation that surely makes mathematicians cringe. What I do know is, over the course of the first week of the Olympics, the number has been in the ballpark of 30 every day.
What BetterExplained.com doesn’t equate, is the odds of winning a gold medal on your birthday.
Daniele Molmenti probably doesn’t care about those odds.
Don’t know who Molmenti is? He’s the Italian kayak slalom champ running around the Olympic Village on Aug. 1 with nothing but his brand new gold medal hanging around his neck. Happy 28th birthday, Daniele.