Tuesday, 30 December 2008

The Monty Hall Problem

My mind is still spinning with the Monty Hall Problem. The problem is easy to understand but the solution is completely counterintuitive. It’s really weird – maybe we are just hardwired to be stupid. Try the problem yourself and see if you are stupid too. But even if you are, don’t get too upset about it – you are in good company and virtually EVERYONE unfamiliar with the problem will get it wrong – even if they have a bloody Phd or MBA after their name!

In fact this is a good problem to give to people who claim that education is everything. It is not. Education is, of course, important but it’s far more important to be actually able to think. After all, there are many educated idiots out there: you know the sorts of people I mean – the buffoons in suits that say that stock prices and house prices will always go up… Yeah right… Roll on 2009…

Okay, let’s get down to the problem which refers to Monty Hall, the host of a TV game show called "Let's Make a Deal".

The game show made him very popular in the 1960s and 1970s and then you’d think that that would be that.

But it wasn’t. Cos some years later in 1991, a reader of Marilyn Vos Savant's Sunday Parade column wrote in and asked:

The Monty Hall Problem
"Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the other two are goats. You pick a door, say No. 3, and the host, who knows what's behind the other doors, opens another door, say No. 1, which has a goat. He then says to you, 'Do you want to pick door No. 2?' Is it to your advantage to accept the offer to switch?"

Now most people would not bother to switch. After all, if there are now two cards left and the car is behind one of the doors, you must have an equal chance of being correct surely?

Well wrong. Absolutely wrong.

Cos you’d be far better off switching.

Play the game here and read the mathematics here.

Well, I’m just off to watch Deal or No Deal. It’s a whole lot easier to understand. And the girls aren’t too bad either…

 Deal or No Deal


wankongyew said...

Heh, this, along with the gender of the child in the window problem, and the plane on a treadmill problem, is guaranteed to have appeared at least once on every forum on the Internet with a substantial population.