Probably the most confusing blog in the world

A: I’ve been reading about probability this week.

B:Are you sure?

A: Yes. There’s a very interesting problem concerning 2 goats and a car.

B: Shoot.

A: OK. Stay with me for this – it’s a bit tricky.

B: OK.

A: On a tv show contestants can win either a goat or a car.

B: Why?

A: Because……. I don’t know – perhaps they’re Capricorns?

B: If they were Pisces?

A: It would be 2 fish and a car I guess.

B: You digress.

A: I do. There are 3 doors on this t.v. show and behind each door is either a goat or a car.

B: 2 goats. 1 car.

A: Correct. And before you ask – you can’t hear or smell the goats.

B: Or the car?

A: Or the car.

B: Go on.

A: The host asks the contestant to choose a door. The winning contestant chooses a door.

B: Door number 1, 2 or 3.

A: If you like.

B: I like. Oh by the way does the host know where the car and goats are?

A: Yes. This is important.

B: Glad I asked.

A: OK. So the contestant chooses 1, 2 or 3. Then comes the intriguing part.

B: What – the door is opened.

A: No. The door isn’t opened

B: What happens?

A: Well, the host opens one of the doors not choosen to reveal a goat.

B: Whilst the contestant…

A: Whilst the contestant still has the door they’ve already choosen. They may even stand by it – if they like.

B: Intriguing.

A: That’s not the intriguing part. The next bit is.

B: Pray tell.

A: Well the host then asks the contestant if they want to change their mind.

B: And?

A: And invariably the contestant says ‘no’. How crazy is that?

B: Not that crazy.

A: It’s ridiculous.

B: Why?

A: Well – if the contestant changes their mind they have twice the chance of winning the car, of course.

B: Of course (pause). I see it now?

A: No you don’t. But it is true though. Trust me. It’s maths.

B: And this proves?

A: That it’s often difficult to adapt – change your perspective – change your TOR.

B: Tor? Mountain? Get to the top of the tor and change your point of view?

A: Terms of Reference.

B: I knew that. But seriously, talk me through the goat thing.

A: Well – it’s to do with where you are.

B: (A long drawn out) OK…..

A: At the start you choose a door and have a 1 in 3 chance of getting the car. Right?

B: Check.

A: When you’re asked if you’d like to change your mind the TOR are different.

B: (A longer drawn out) O.K…………

A: Look at it from the point of view of the prize behind the door that the contestant hasn’t chosen and hasn’t been opened.

B: I can do that.

A: If you’re a car – you won’t be opened – obviously.

B: Obviously. Because …?

A: Because you’re a car and the host wouldn’t give the game away.

B: Ah ha.

A: So therefore you have a 2 in 3 chance of being a car…

B: Because there are only 3 options for the doors that are not the contestant’s choice….

A: Which are a) car/goat, b) goat/car or c) goat/goat.

A: Exactly.

B: So by eliminating the goat as an option in all three

A: You are left with options …a) car b) car or c) goat.

B: So as a contestant if you worked this out you know…

A: You would change…. QED.

B: Quite Easily Done?

A: Quod Erat Demonstrandum.


Published by: byron kalies

Writer, golfer and golf writer, I have developed and moved on (not permanently in case there are any publishers reading this) from the relatively straightforward world of management consultancy with motivation, leadership, change matrices, decision making, communication, customer care, bottom lines, double-loop learning, stress, attribution theory, behavioural interviewing, project management, group think and Johnson and Scholes’ Cultural Web, to the complex and unfathomable world of describing places where people can hit a ball into a hole. I have written for a number of golf magazines and newspapers including 'Golf International' , 'wales on Sunday' and am currently golf correspondent for Cambria Magazine (Wales's Magazine) and blogger for Wales Online.

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