(no subject)

[plonq]

I made the mistake of bringing up the "Monty Hall" theorem yesterday.  That entailed 30-minutes of diagrams and explanation to convince a co-worker of the answer.  At one point I actually ran some simulation software for him to illustrate the odds in practise.

He still didn't get it.  "It's 50/50 I tell you!"

I finally drew a multi-coloured grid to represent the three doors in all three states, and it finally clicked for him.  He grudgingly admitted that, as counter-intuitive as the answer is, he could see that it worked.  I'll have to keep this diagram in mind the next time I feel masochistic enough to bring this one up again.

Comments

[leopanthera.livejournal.com]

It would be 50/50 if the game show host picked a door at random. But he doesn't, he can't, he knows which is the "bad" door and cannot choose that one.

It's easier to understand once you realise that fact.

[plonq.livejournal.com]

Yes - thank you! That is the key to the answer.

The game host is not random.

I thought that I was going to go horse from repeating that phrase yesterday. Oy. Ultimately I saved a thousand more words by drawing a picture. ;)

[plonq.livejournal.com]

Er, make that "hoarse".

[mwalimu.livejournal.com]

The basic reasoning becomes much clearer if instead of three doors, with Monty opening one, you change it to have a hundred doors, with Monty opening ninety-eight.

[plonq.livejournal.com]

Ah, I've employed that argument too, but it always comes back to the same counter-argument.

"But once it's down to two doors, it's 50/50...!!!"

(The three exclamations are the staccato sound of my head thumping the desk.)

[tzisorey.livejournal.com]

Technically that's correct.... once it's down to 2 doors it's 50/50. But that's when you're already half-way through the game.