Another silly quizz

[gatso]

and btw, the question is incomplete. it's not actually possible to know the correct answer without some additional information on the actions of the host

[kinboshi]

and btw, the question is incomplete. it's not actually possible to know the correct answer without some additional information on the actions of the host

The question is complete.  He shows you a goat, so you know it's correct to switch.

[kinboshi]

I got the first one wrong as well.

[MereNovice]

17/20.
Question 20 completely stumped me and I didn't read the ante-antepenultimate question properly - silly me. Got the first three letters right then jumped to the wrong conclusion.

[gatso]

and btw, the question is incomplete. it's not actually possible to know the correct answer without some additional information on the actions of the host

The question is complete.  He shows you a goat, so you know it's correct to switch.

oops, sorry didn't read the question fully. you improve your chances to win if the host a) knows where the car is and b) always offers the switch. if these conditions are not in place then things may be different.

I skimmed over the question and missed that the switch was already offered pre selection

btw kin your reply is incorrect, it's not correct to switch because he shows you a goat. it's correct to switch because you knew he would show you a goat and you knew he would offer you the switch

[Compo]

The goat question, or a variety of, is/was used by a a well known betting tycoon during all job interviews. Any mug that said change, because the odds changed after being shown the goat was summarily shown the door. Changing your selection is no different,in odds terms, than waiting for six tails on a coin flip then betting on heads. In both examples when you make your first selection you are either right or wrong. If right well done. If wrong changing your selection doesn't alter the true odds. It's only 50/50 if you have two to choose from at the start ie. heads/tails. In the goat example you are 2/1 to get it right,33%, or 1/2, 66%, to get it wrong. If you believe that to change your selection is good then you are 50% to get it wrong. Overall that makes it more than a certainty, 116%, that you will be wrong. Clearly that is impossible, but it does show that the odds can't change once the game starts.

[gatso]

The goat question, or a variety of, is/was used by a a well known betting tycoon during all job interviews. Any mug that said change after being shown the goat was summarily shown the door. Changing your selection is no different,in odds terms, than waiting for six tails on a coin flip then betting on heads. In both examples when you make your first selection you are either right or wrong. If right well done. If wrong changing your selection doesn't alter the true odds. It's only 50/50 if you have two to choose from at the start ie. heads/tails. In the goat example you are 2/1 to get it right,33%, or 1/2, 66%, to get it wrong. If you believe that to change your selection is good then you are 50% to get it wrong. Overall that makes it more than a certainty, 116%, that you will be wrong.
That is why you don't change your original selection.

that is true in a vacuum but that is not the case here. if, as is the case here, you know in advance that you will a) be shown the goat and b) be offered the switch then it is correct to switch as you become a 2/1 fave to win. mathematical proof is here http://en.wikipedia.org/wiki/Monty_Hall_problem

without those 2 criteria being in place then the answer changes. in some cases (if you are always shown a goat but only offered a switch if your original choice was correct) it is always correct to stick with your original choice. other variables alter the odds towards either switching or sticking

[MereNovice]

The clearest explanation that I have found of why it is correct to change is here:- http://math.ucsd.edu/~crypto/Monty/montybg.html
It comes complete with some very nice pictures.

Anyway, who is this "betting tycoon" - I think we deserve to be told.

[Compo]

The clearest explanation that I have found of why it is correct to change is here:- http://math.ucsd.edu/~crypto/Monty/montybg.html
It comes complete with some very nice pictures.

Anyway, who is this "betting tycoon" - I think we deserve to be told.

Monty Hall

[MereNovice]

He must have been a busy man with all his television commitments as well.

[kinboshi]

and btw, the question is incomplete. it's not actually possible to know the correct answer without some additional information on the actions of the host

The question is complete.  He shows you a goat, so you know it's correct to switch.

oops, sorry didn't read the question fully. you improve your chances to win if the host a) knows where the car is and b) always offers the switch. if these conditions are not in place then things may be different.

I skimmed over the question and missed that the switch was already offered pre selection

btw kin your reply is incorrect, it's not correct to switch because he shows you a goat. it's correct to switch because you knew he would show you a goat and you knew he would offer you the switch

If he knows where the goat is, it means he obviously knows where the car is.  Because he will always show a goat to you, from the two you haven't picked that makes it more likely that the goat will be in the one you didn't pick, rather than the one you did pick.

I think we're actually in agreement here.

[MereNovice]

I think EVERYONE is in agreement here apart from Compo who is in serious denial.

[gatso]

and btw, the question is incomplete. it's not actually possible to know the correct answer without some additional information on the actions of the host

The question is complete.  He shows you a goat, so you know it's correct to switch.

oops, sorry didn't read the question fully. you improve your chances to win if the host a) knows where the car is and b) always offers the switch. if these conditions are not in place then things may be different.

I skimmed over the question and missed that the switch was already offered pre selection

btw kin your reply is incorrect, it's not correct to switch because he shows you a goat. it's correct to switch because you knew he would show you a goat and you knew he would offer you the switch

If he knows where the goat is, it means he obviously knows where the car is.  Because he will always show a goat to you, from the two you haven't picked that makes it more likely that the goat will be in the one you didn't pick, rather than the one you did pick.

I think we're actually in agreement here.

we are in agreement, don't think compo is though, do you want to see if we can swap a goat for his car @ luton?

[kinboshi]

and btw, the question is incomplete. it's not actually possible to know the correct answer without some additional information on the actions of the host

The question is complete.  He shows you a goat, so you know it's correct to switch.

oops, sorry didn't read the question fully. you improve your chances to win if the host a) knows where the car is and b) always offers the switch. if these conditions are not in place then things may be different.

I skimmed over the question and missed that the switch was already offered pre selection

btw kin your reply is incorrect, it's not correct to switch because he shows you a goat. it's correct to switch because you knew he would show you a goat and you knew he would offer you the switch

If he knows where the goat is, it means he obviously knows where the car is.  Because he will always show a goat to you, from the two you haven't picked that makes it more likely that the goat will be in the one you didn't pick, rather than the one you did pick.

I think we're actually in agreement here.

we are in agreement, don't think compo is though, do you want to see if we can swap a goat for his car @ luton?

Maybe we should show him the door?

[sweet potata!]

Lol , that didnt go too well !......I liked that goat question though