You learn all about this stuff in psychology. Unfortunatly I left my textbook back home. Let me see what I can find for you pigeon.

Here's some stuff about it on Wikipedia. It's still kind of confusing, but it explains it better than I could. By the way, it's called the Monte Hall Problem.

http://en.wikipedia.org/wiki/Monte_Hall_Problem

I don't see what's so hard with this, basically you have 3 choices in the begining. So choosing the car is a probablity of 1/3 at the start.

Revealing one card shows that one is a goat. The choices now with the one card missing is 2/3. So if you switch your choice your chance of winning is higher.

Everyone knows the chances of winning anything are 50/50. Either you win or you don't.

Raytrace, you've just convinced me to go and buy a powerball ticket.

I bet if you did two sets of 100 trials switching and 100 trials not switching, in both cases you'd probably win about 33 times.

This all boils down to combination theory from Monty Hall.As one other member has illuded to.
Though this video is obviously staged because of the random part of chance that could ruin it

Shows there are some very good reasons to do a Maths Degree, Gambling.

Could you not argue that sticking with your choice is a choice between the two anyways?

Yes, but mathematically your choices do increase if your switch your choice.

I am confused. This is why I dropped stats. Here is an applet which apparently proves this theory.

http://www.stat.sc.edu/~west/javahtml/LetsMakeaDeal.html

I just can't accept it!

There's more of these Numb3rs clips at http://shuzak.com/Personal/Mathematics-In-Numb3rs.php?ID=6 ...

I can't get into the show since I am not crazy about CSI types of shows. Math is kind of cool, but I suck at it.

The thing that made this less counterintuitive for me:

When Monte opens one of the doors, he is not choosing at random: he never opens the door that has the prize behind it. That's what throws the (expected) probability off.

Consider that you have 100 doors with 99 goats and 1 car. You pick 1 door, and the host opens 98 doors with goats behind them. Do you switch or not? It's the same reasoning here

No. It's this simple concept (with 3 doors).

- You randomly pick a door (2/3 time you pick a goat)
- Monty shows you a goat
- If you initially picked a goat, then switching now means $$$ (2/3 odds)
- If you initially picked the money, then you lose, but this only happens (1/3 odds)

actually it IS the same reasoning joedirt, http://en.wikipedia.org/wiki/Monte_Hall_Problem
has that specific example. Its just a means of exaggerating the scenario to help people who are having problems understanding it.

I like to think of it this way. No matter what you pick, a goat will be revealed. When you pick a door, you limit the options for revealing the goat to only two doors. It is like saying "show me one of the goats, but you can't open the door I select to do it."

Tags for this video have been changed from 'numb3rs, math, probability' to 'numb3rs, math, probability, monty hall problem' - edited by xxovercastxx

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