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You're on a game show and there are prizes behind three doors. Behind one door is the star prize, a lifetime pass to see the Swans and behind the other two doors is a free dental consultation. The game show host knows where both dental consultation prizes are. You choose a door then the game show host opens one of the doors with the dental consultation prize leaving you with a straight choice - stay with your original choice or change to the other available door. So, which choice would be more likely to yield the star prize - stick or change - or would it not make a difference either way?
[Post edited 23 Jan 2015 0:51]
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Lifetime Swansea City pass or a visit to the dentist on 00:56 - Jan 23 with 4271 views
Lifetime Swansea City pass or a visit to the dentist on 00:56 - Jan 23 by swanduck
I swear I read somewhere in that sort of situation you should always swap! Can't remember where I read it though.
when you chose first you had a 1 in 3 chance of being right and a 2 in 3 chance of being wrong.
When 1 door is opened, it doesn't change the original odds. Therefore if you stick, you still have a 1/3 chance of being right and a 2/3 chance of being wrong. By switching, you've just doubled your odds of being right (mathematically).
Of course in practice, sods law would apply ...
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Lifetime Swansea City pass or a visit to the dentist on 06:20 - Jan 23 with 4193 views
Lifetime Swansea City pass or a visit to the dentist on 01:03 - Jan 23 by londonlisa2001
when you chose first you had a 1 in 3 chance of being right and a 2 in 3 chance of being wrong.
When 1 door is opened, it doesn't change the original odds. Therefore if you stick, you still have a 1/3 chance of being right and a 2/3 chance of being wrong. By switching, you've just doubled your odds of being right (mathematically).
Of course in practice, sods law would apply ...
It's a bit like the spin of a roulette wheel after a number has just come up. Mathematically it reduces the odds of that number coming up again on the next spin but of course any number can come up. That's why I don't play roulette very often.
The real slackjack .... beware of imposters! They say that imitation is the sincerest form of flattery ......... Enough said!
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Lifetime Swansea City pass or a visit to the dentist on 06:54 - Jan 23 with 4179 views
Lifetime Swansea City pass or a visit to the dentist on 06:20 - Jan 23 by s1ackjack
It's a bit like the spin of a roulette wheel after a number has just come up. Mathematically it reduces the odds of that number coming up again on the next spin but of course any number can come up. That's why I don't play roulette very often.
The wheel doesn't know. But who's ever seen a quadruple spin?
Lifetime Swansea City pass or a visit to the dentist on 13:12 - Jan 23 by GreatBritton
The wheel doesn't know. But who's ever seen a quadruple spin?
the chances of the same number coming up 4 times in a row are exactly the same as any other combination of 4 named numbers. It's just that you notice it more. From time to time there'll be what looks like patterns, but it's all just pure chance. Roulette is, as all games, biased towards the casino due to the presence of non 'red or black' on the wheel yet all the odds are calculated for payouts as though there is only red and black. The difference between those two calculations is the money that the casino will always make over the long term.
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Lifetime Swansea City pass or a visit to the dentist on 13:30 - Jan 23 with 3971 views
Lifetime Swansea City pass or a visit to the dentist on 13:30 - Jan 23 by dickythorpe
This is a thinly veiled "isnt Maths fun thread".... WELL IT FECKING ISNT RIGHT!!!!!
ha ha.
Some of it is quite fun though and it can be a good way to have a good bet when the maths is counter intuitive.
A really good one is if there's a room of people and you have a bet on whether anyone shares a birthday. Because of the way the maths works, if there are about 30 people together, it's almost certain that 2 will share a birthday. But logically, everyone will think, there's only 30 of us and there are 365 days in the year so it's only about a 1 in 10 chance. So people will take the bet on, and you'll win almost every time (since it's actually 1 in 10 that any one of them will share a birthday with another one - by the time you add the odds up over the 30 someone will almost certainly have a birthday in common). Try it.
One thing is for certain - maths is taught really badly and people think it's dull, whereas actually it's anything but.
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Lifetime Swansea City pass or a visit to the dentist on 13:41 - Jan 23 with 3942 views
Lifetime Swansea City pass or a visit to the dentist on 13:38 - Jan 23 by londonlisa2001
ha ha.
Some of it is quite fun though and it can be a good way to have a good bet when the maths is counter intuitive.
A really good one is if there's a room of people and you have a bet on whether anyone shares a birthday. Because of the way the maths works, if there are about 30 people together, it's almost certain that 2 will share a birthday. But logically, everyone will think, there's only 30 of us and there are 365 days in the year so it's only about a 1 in 10 chance. So people will take the bet on, and you'll win almost every time (since it's actually 1 in 10 that any one of them will share a birthday with another one - by the time you add the odds up over the 30 someone will almost certainly have a birthday in common). Try it.
One thing is for certain - maths is taught really badly and people think it's dull, whereas actually it's anything but.
You are beyond help - have a lie down.
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Lifetime Swansea City pass or a visit to the dentist on 13:42 - Jan 23 with 3941 views
Lifetime Swansea City pass or a visit to the dentist on 06:20 - Jan 23 by s1ackjack
It's a bit like the spin of a roulette wheel after a number has just come up. Mathematically it reduces the odds of that number coming up again on the next spin but of course any number can come up. That's why I don't play roulette very often.
There are certain tactics you could use on a roulette table that would get you chucked out, they don't like the odds not favouring the house, same with pontoon but there you go.
Continually being banned by Planet Swans for Porthcawl and then being reinstated.
Lifetime Swansea City pass or a visit to the dentist on 01:03 - Jan 23 by londonlisa2001
when you chose first you had a 1 in 3 chance of being right and a 2 in 3 chance of being wrong.
When 1 door is opened, it doesn't change the original odds. Therefore if you stick, you still have a 1/3 chance of being right and a 2/3 chance of being wrong. By switching, you've just doubled your odds of being right (mathematically).
Lifetime Swansea City pass or a visit to the dentist on 13:38 - Jan 23 by londonlisa2001
ha ha.
Some of it is quite fun though and it can be a good way to have a good bet when the maths is counter intuitive.
A really good one is if there's a room of people and you have a bet on whether anyone shares a birthday. Because of the way the maths works, if there are about 30 people together, it's almost certain that 2 will share a birthday. But logically, everyone will think, there's only 30 of us and there are 365 days in the year so it's only about a 1 in 10 chance. So people will take the bet on, and you'll win almost every time (since it's actually 1 in 10 that any one of them will share a birthday with another one - by the time you add the odds up over the 30 someone will almost certainly have a birthday in common). Try it.
One thing is for certain - maths is taught really badly and people think it's dull, whereas actually it's anything but.
I don't think your arithmetic is quite right there, Lisa.
With a group of about 30 people, the odds of 2 people having the same birthday is about 50/50?
EDIT - I actually just did this on my trusty Shaky calculator - turns out it's actually about 70/30 in favour (if you ignore weirdos with Feb 29 birthdays). Still not virtually certain though :)
[Post edited 23 Jan 2015 15:59]
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Lifetime Swansea City pass or a visit to the dentist on 17:22 - Jan 23 with 3780 views
Lifetime Swansea City pass or a visit to the dentist on 15:54 - Jan 23 by jackonicko
I don't think your arithmetic is quite right there, Lisa.
With a group of about 30 people, the odds of 2 people having the same birthday is about 50/50?
EDIT - I actually just did this on my trusty Shaky calculator - turns out it's actually about 70/30 in favour (if you ignore weirdos with Feb 29 birthdays). Still not virtually certain though :)
[Post edited 23 Jan 2015 15:59]
no, you're right - 30 wasn't the right number - I din't calculate it - it was from memory. It hits 90% likelihood at 42 people.
Pretty good odds though even at 30 people on a bet.
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Lifetime Swansea City pass or a visit to the dentist on 17:30 - Jan 23 with 3774 views
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