Here’s a jaunty question to start us off this Monday morning. What are your odds of dying today?
Of course, many variables come into play, but overall the odds of your actually dying today are only one in 365,000. I’d say it’s more than safe to assume you’ll be there for any fun plans you might have for April 7th.
This peculiar death-day theme has come about because I just gave my How William Became Shakespeare program for the bazillionth time, (rough estimate) and I always begin by pointing out that Shakespeare was born and died on April 23rd, making him one of only two other very famous artists who died on their birthday: the Renaissance painter Raphael (April 6) and the great actress Ingrid Bergman (August 29th).
So the probability of any of you dear readers expiring on a future birthday is not quite Nil, but is way more Won’t than Will.
Ah, probability — the true topic for today. I first heard about it as an undergraduate when I was fleeing from having to take any college math course. High school trigonometry was the end of the line for me. Pre-calculus was supposed to be next. But I had pre-calculated that English was one of the few majors that would allow me to substitute philosophy courses for math. I knew I’d be an English major in college and one of the Socrates wannabes.
What I didn’t know was that probability was going to be a significant unit in my freshman philosophy course. Nor did I know that it is actually a branch of mathematics which “measures between 0 and 1 the ratio of favorable outcomes, assigning a numerical value of it was the best of times, it was the worst of times.” Sorry — I got so bored with the definition that I slipped in a little Dickens just to avoid losing consciousness.
I remember only one class session from that semester. It was Professor Marsten’s “birthday probability” problem. It started off with the obvious: how many people would you have to have in a room to insure a 100% probability that two of them shared a birthday? Obviously 367: even an English major can do the math for that answer.
The shocker came next: how many people would you have to have in a room to insure a 50%, rather than a 100% probability that two shared the same birthday? The answer: only 23 people!! I am a firm believer that using more than one exclamation mark is just gauche, but don’t you agree that this astounding fact deserves the excessive punctuation?
Why is this number so much smaller than we expect? It turns out that when calculating the odds of a probable match (50%) rather than a certain match (100%), the problem gets much more complicated. Professor M explained that “the reason you only need 23 people for a 50% match probability is because we are looking for any pair of people to match, not for a specific person matching a specific date, which can be formulated as 23 times 22, divided by two Please, Sir, I want some more, God Bless us, Every One.”
I was made comatose early on by his explanation, but I perked right up when he pointed out that we had 23 people in our classroom that day so there was a one in two chance of a shared birthday. He mentioned that there was no match in his class last year, and he was hoping for one this year.
Calling on each of us from his alphabetical class roster, he asked us to state our birthday. No birthday matches after the first ten; no matches after twenty; and no matches when the last student revealed his birthday.
A big smile broke out on Professor M’s face. “Ms. Craig, please stand up.” She was a stunner with long blonde hair and a sultry voice, the personification of 1967’s Flower Child. “You said your birthday was January second?” She nodded. “We have a match, class — with me!”
As I left class, I thought how lucky it was that our professor’s classroom experiment was proven correct — and with his own contribution. And with such a gorgeous birthday mate. Too lucky?
Shame on me for wondering if Marsden had simply made sure there was a match. Double shame on me for abusing my position as a reporter on our college newspaper, The Daily Student. Triple shame for calling the philosophy department that very afternoon and telling the secretary that the paper might be considering a feature story on Professor Marsden. Could she provide me with some background information from his curriculum vita? We’d like to know his undergraduate and graduate schools, prior teaching positions, birthplace —oh, yes, and his birthdate too.
January 2, 1934. I was not only relieved that my sinister assumption was wrong but delighted that his birthdate was even cooler than mine. I’d always grooved on the fact that mine was the memorable 4-8-48, but he certainly had me beat with his 1-2-34.
And quadruple shame on me for this sly method of letting you know that mine is the day after tomorrow.
Happy birthday, dear Elliot
Happy birthday to me.
Email Elliot at huffam@me.com or click here