How do you get to Monty Hall

I was in Budapest recently for a short break. Whilst there I had the joy of seeing those four mexican pan pipe players that I seem to see every place I ever travel to. When I got to Venice the first people I saw getting out of the train station was four banditos playing pan pipes, same in San Francisco, and Barcelona. I have come to the conclusion its the same four blokes following me around in some CIA operation. How else could they also turn up at my local shopping centre!
Well not only are the four banditos following me around, but apparrently so is Deal or No Deal. Having enjoyed a goulash based dinner I returned to my hotel and flicked on the TV. Having got quite bored of BBC World (which has no point at all.... and I thought BBC4 was bad), and Eurosport (when you find yourself riveted to Sumo Wrestling you know something isn`t right with the world) I started flicking through the remaining foreign channels (hey its was post 10 p.m. there was always the chance of softcore porn!).

What I did come to however was the Italian version of Deal or No Deal. I`m afraid the presenter was a little more suave than Noel TidyBeard, and his shirts weren`t as loud, but the woman playing the game made up for the loudness. I came in right at the end and she had just two boxes left, 250,000 euros and 250 euros. The bankers offer was 80,000 euros. I don`t speak Italian but all I can tell you is she went on a 14 minute monologue - there was crying, there was wailing, family members sobbed (I am guessing at one stage she had offered to give her brother a kidney or something). Even the woman`s boyfriend was trying to get her to actually pick a box and get the hell on with it. What makes me laugh with these things is that rather than actually understanding they are leaving with more money than they came with regardless, to them these choices seem to be the equivalent of a scene from Rosemary`s Baby.

She decides to decline the offer of 80,000 and is going to pick one of the boxes. She is then given the option to swap the box. Its at this point I start shouting at the screen. "Swap the box, swap the box. Monty Hall means you have to swap the box!"

So for any of you who ever find yourselves on Deal or No Deal, I am going to tell you all about the Monty Hall problem and why, if you are ever offered to swap the box, you have to swap the box.

In the 60`s there was an American tv game show. Finalists were invited up onto the stage, where there were three closed doors. The host, Monty Hall, explains that behind one of the doors is the star prize - a car. Behind each of the other two doors is a goat. Obviously the contestant wants to win the car, but does not know which door conceals the car.

The host invites the contestant to choose one of the three doors. Let us suppose that the contestant chooses door number 3. Now, Monty Hall does not initially open the door chosen by the contestant. Instead he opens one of the other doors - let us say it is door number 1. The door that the host opens will always reveal a goat. Remember Monty knows what is behind every door!

The contestant was then asked if they want to stick with their original choice, or if they wanted to change their mind, and choose the other remaining door that has not yet been opened. In this case number 2. The studio audience shout suggestions. What is the best strategy for the contestant? Does it make any difference whether they change their mind or stick with the original choice?

This is not an example of simple probability (suppose there are two doors, therefore there is a 1 in 2 chance of the car being behind either of the doors). This is an example of conditional probability: what is the chance of something happening, given that something else already has.

Their chance of being right initially is still only 1 in 3. But now the host opens a door revealing a goat, and the contestant changes their mind - and 2 times out of 3 they will be right. So, if the contestant sticks with their original choice, they will win the car 1 time in 3, and if they switch doors, they will win the car 2 times in 3. Though this may sound rubbish this is a well known probability problem that has been known to maths men and women for over a hundred years. I guarantee if you try the game yourself you`ll find you win the car more often by swapping the door. Still don`t believe me, check out this blokes whizzy simulator:

http://www.grand-illusions.com/simulator/montysim.htm

So now look at this in the context of Deal or No Deal. You have 22 boxes. If you get down to the last two then your chances of having the jackpot in your first chosen box is 1 in 22, whereas, using the Monty Hall theory, the chances of it being in the other box is 21 in 22. So you have to swap the box.

So we go back to that poor Italian woman, screaming her head off. She has turned down the offer. She also decides NOT to swap the box, which means she now only has a 1 in 22 chance of winning the jackpot......

Her box is opened......

It has 250,000 euros in it!

Well there was always a 1 in 22 chance that she got the right box, and this time she did. Lucky cow! See, its these type of people, those who only have a one in 22 change of beating you, and then frequently go on and do, that makes poker so infuriating sometimes (see you knew I couldn`t get to the end without mentioning poker!)

My major question about all of this is nothing to do with the counter intuitive probability, but whether, if you chose the goat rather than the car, you actually got to take the goat home?




Pot total: $430.23 ($52.23 increase from last blog)

Robbing the Bank

Now now children, sit down, its time to start the lesson. Jones, I told you to take that crayon out of your nose, it won`t help dislodge the action man hand you stuck up their yesterday, just leave it alone!

Okay, so its that time for a lesson. And that lesson is Bankroll management. Yes you can all stop yawning and moaning, I know its boring, but it has to be talked about.

Well that was the plan 2 weeks ago anyway. Two weeks ago my pot stood at a healthy $440, however during a most ridiculous run of bad luck (straights from no where beating aces, and more annoyingly being beaten by a bloke three times with Jacks each time). So now my pot stands, ridiculously at the exact same it did this time last month $378. However to loose that much in a run in two weeks has been gutting.

I will however mention bankroll management. Proper poker money management suggests that, so as not to go bankrupt, but at the same time not to take years to earn some money, that you should always work on the principal of playing at a level that equates to 30 times your buy in. So for example if you were to play in a 10 player $10 sit and go, you would need to have $300 in your pot to make sure you are able to deal with the ups and downs and show a good profit with good poker.

Now any of you paying special attention (or even reading any of this diatribe) will realise that my pot is currently $378 but I am playing at $5 sit and go level. Clearly way under the level I should be playing at. Well what can I say I am a cautious soul... and if you met my parents where risk is having a chinese rather than indian takeaway on a Friday night, you`d understand why.

Originally I had been hoping to be at around the $500 mark when writing this, and as such suggest that I work on the principal of playing at 50 times the buy in. However what has been concerning me is the quality of players I have been playing recently. Namely they are bad and lucky. I don`t mean this as a sob story, but its beginning to take the piss. So, dear reader, the decision has been to take an even between the two. I will start playing at 40 times the buy in. Which means, if I reach $400 by my next blog post, I will be playing in the $10 buy in. Holy crap! Admittedly with the exchange rate as it is that probably works out at 30p, but thats beside the point.

Wish me luck people - if there are any of you out there!

Oh and feel free to write a comment on any of this drivel. Otherwise I wonder if I am just talking to myself. My therapist doesn`t think thats a good thing. Neither do the other three voices in my head.

Byeeeeeee.


Pot total: $378 (0 increase from last blog)