The Reverse Betting Agency [spoilers]

[Tass]

Hello and welcome to the reverse betting agency!

I thougth that the betting agency of the playground (http://www.giantitp.com/forums/showthread.php?t=26243&highlight=betting+agency) was a brilliant idea, and was really sad that Silkenfist had to abandon it. I will therefore present something like it, and yet different.

Just like the original you will be playing for Anticipation Derived Dollars (ADD), but in this game you will be chosing the odds.

Every saturday I will chose one or more "this-or-that" questions, and you will have till monday to set the propabilities as you think they are, by post here or PM. Default will be 50/50. When a question is resolved you will recieve an amount of ADD equal to the logaritm of twice the probability you gave that outcome, multiplied by 100 to make the numbers fall in a nice range.

In example: I ask A or B?

Alice says: A 70%
Bob says: B 80%
Claire says nothing.

What is registrered is:

Alice: 70/30
Bob: 20/80
Claire: 50/50

Supose A turns out true, the result will be:

Alice 33,6 ADD ln(0.7*2)*100=33,6
Bob -91,6 ADD
Clarie 0 ADD

The default 50/50 gives nothing either way, since no prediction was made, and ln(1)=0. The more certain you are of an outcome, the more you can win, but likewise you will loose more if it turns out to be wrong.

Hope you will join the game, first question will be up on saturday, enjoy.

Results:

69,3 ADD V Junior
15,8 ADD BobTheDog
-69,3 ADD Gashad
-54,8 ADD GoC
-55,2 ADD Battleburn
-102,2 ADD Ave
-156,5 ADD Jindra34

Result of Miko apearance:

47,0 Battleburn
27,8 BobTheDog
18,2 GoC
9,5 Jindra

Result of the two question about Roys fall

69,3 ADD V Junior
-12,0 ADD BobTheDog
-69,3 ADD Gashad
-73,4 ADD GoC
-102,2 ADD Ave
-102,2 ADD Battleburn
-166,0 ADD Jindra34


Active questions:

Will Roy get resurected before zombification and %480?

The_Rogue_Monk 95/5
jindra34 35/65
Frigs 80/20
Thorfluff 0/100
Reed 35/65
MusScribe 83/17
BobTheDog 55/45
Curunir 70/30
Homer HT 85/15


Will Xykon get to touch the saphire?

Jindra34 79/21
BobTheDog 33/66


Open questions:
Will Tsukiko survive the next comic featuring her?

[Silverlocke980]

Okay!

I'm looking forward to it!

[Tass]

Okay!!! Here we go.

Three questions for today:

I: Will Roy use the "booty talisman" during his fall?
A Yes
B No

II: Will Miko appear in the stips in the following week?
A Yes
B No

III: Will Roy land outside of Azure City
A Yes
B No

Footnotes: Appearence is as defined in the "number of appearences" thread. Being saved obviously counts as "no" in III. Last chance for predicting is monday 12.00 eastern standard time, or when new comic is up. Note: Question two is changed so it is not misunderstood. All who voted 0% because of that is reset to 50/50. Feel free to change your odds again.

[Demented]

Huh.
If I vote A: 99/1 for anything, if A, I will gain 68 ADD; if B, I will lose 391 ADD. Bad trade.
If I vote A: 51/49 for anything, if A, I waill gain 2 ADD; if B, I will lose 2 ADD. Even trade.

But that's not the best part.

If I vote A: 100/0 for anything, if A, I will gain 69 ADD; if B, I will lose an... indeterminate amount of ADD. Say what?
If I vote a negative probability, it's ALL indeterminate. Or, more likely, all my ADD will be numbered as i.

[Sean92k]

Do we pm you?

[GoC]

I: Will Roy use the "booty talisman" during his fall?
A Yes 80%
B No 20%

II: Will Miko appear in the stips this week?
A Yes 40%
B No 60%

III: Will Roy land outside of Azure City
A Yes 60%
B No 40%

[jindra34]

1.going A 95%
2.going B 55%
3.going B 95%

[BobTheDog]

I - B 66,6%
II - B 66,6%
III - B 66,6%

Two thirds!

[V Junior]

1: A at 50/50, it could go either way.

2: B at 100/0, because THE WEEK IS OVER.

3: A at 100/0, because we know that the dragon was outside Azure City when the dragon's head was lopped off.

[Ave]

1 70% he will use the talisman
2 0% Miko will appear
3. 30% Roy will land outside (if he uses talisman, he won't land)

[Gashad]

75% A,he will use the tailsman
50% A, Miko will appear
75% B, he will land inside

[Tass]

Huh.
If I vote A: 99/1 for anything, if A, I will gain 68 ADD; if B, I will lose 391 ADD. Bad trade.



How is that a bad trade? You will be almost certain to win 68ADD, only a very slim chance of losing 391ADD. Your expectationvalue will be 0.01*(-391)+0.99*68=63,4.
Good trade.




But that's not the best part.

If I vote A: 100/0 for anything, if A, I will gain 69 ADD; if B, I will lose an... indeterminate amount of ADD. Say what?
If I vote a negative probability, it's ALL indeterminate. Or, more likely, all my ADD will be numbered as i.

If you vote 100/0 and lose you will be set to minus infinity ADD, wich means you will effectively be out of the game. But this shouldnt worry you if you are a hundred percent certain of the outcome. If you acknowledge that the loss could happen, then you shouldn´t vote 100/0 (which noone obviously should).

The formula is designed so that your best probability estimate will give the best result, on average. I shall prove this later.

Negative probabillities is ill defined and obviously not allowed.

[battleburn]

To make sure noone cheats you should say that only non-edited posts count. Or just not edited after the new comic came up.

I: Will Roy use the "booty talisman" during his fall?
A Yes; 70%


II: Will Miko appear in the stips in the following week?

B No; 80%

III: Will Roy land outside of Azure City
B No; 70%

The problem is, I think they are outside of the city, but I also think he will use the talisman.

[Tass]

Okay so I and III are resolved. (If I am wrong about III I will correct it later). I am sorry but I have to count I as B, since he didn't manage to use it. This means a big loss for almost everyone.

Results:

69,3 ADD V Junior
-12,0 ADD BobTheDog
-69,3 ADD Gashad
-73,4 ADD GoC
-102,2 ADD Ave
-102,2 ADD Battleburn
-166,0 ADD Jindra34

[BobTheDog]

[edit: browser bug, can't find where the delete button is.]

[BobTheDog]

Huzzah! Second place!

And considering the lack of charging/swarming/dead hobgobs, I still hope he landed inside the city.

[Tass]

Okay, a single question this time:

Will Roy get Raised or Ressurected before he is zombiefied and before Oots #480?
A: Yes
B: No

Alomost everyone won on question II about Miko. I will add this one to the score shortly.

[TRM]

Will Roy Get Raised or Resurrected Before He is Zombified and Before OoTS #480?
A Yes: 95%

[jindra34]

A. No 65% going conservative

[Copacetic]

A, 80% I don't think he's going to be a zombie

[ThorFluff]

Will Roy get Raised or Ressurected before he is zombiefied and before Oots #480?

B: No 100%

Why? To many good jokes, and to much good story otherwise.

[Reed]

B: No 65%
I'm pretty sure he won't be a zombie, but I don't think he'll be resurrected before 480.
Shouldn't those two things ('zombified' and 'raised before 480') have different scores?

[Tass]

B: No 65%
I'm pretty sure he won't be a zombie, but I don't think he'll be resurrected before 480.
Shouldn't those two things ('zombified' and 'raised before 480') have different scores?

I am trying to keep it simple by having only two possibilities. I am thinking of introducing multiple posibillities, in wich case default will be a chance of 1/n and the score will be ln(p*n)*100 . n being the number of options and p the probability given to the winning option.

I am open for suggestions. Also on which questions to ask. The reason for making the betting reverse like this is partly because I wanted to try the idea I had, and partly because it is easy to administer - I do not have to worry about setting odds, but simply choose some questions and calculate the score. Heck, I could even participate myself whithout it being to unfair.

Justification of the formula, for two options warning mathematics ahead:

if the probabilities of x and 1-x is the best probability it is possible to calculate given your incomplete information. We want a function F(y) that makes the expression: x*F(y)+(1-x)*F(1-y) maximal when x=y.

That is when: x*F'(y)+(1-x)*F'(1-y)=0

And since d/dy ln(2y) = 2/y it satisfies it.

I leave it to you to prove that it is indeed a global maximum and not say a local minimum.

[MusScribe]

Let's see...

I'm going with: Yes 83%
(Before zombified - ~90%, Before #480 - ~65%)

[BobTheDog]

Yes 55%

Small bet, for a small gain. :smalltongue:

[Curunir]

Yes 70 %

But I'm not very sure if I'm doing the right thing..

[HomerHT]

Yes, 85%

I'm a gambling man, what can I say? And besides, I have doubts that Roy will still be dead when I'm moving in for school for Fall semester. #480 is ten weeks away...

[Tass]

Question for this weekend?

Will Xykon get to touch the saphire?
A Yes
B No

[jindra34]

A. 79% its almost a given he will touch the saphire. his next act will probably be sitting on the throne.

[BobTheDog]

Question for this weekend?

Will Xykon get to touch the saphire?
A Yes
B No

B 66%

I think he'll be SO close, but no cigar.

[Demented]

A 50%

He has every opportunity to touch it now. The only question is whether he will bother to.

[Tass]

Results:

69,3 ADD V Junior
15,8 ADD BobTheDog
-69,3 ADD Gashad
-54,8 ADD GoC
-55,2 ADD Battleburn
-102,2 ADD Ave
-156,5 ADD Jindra34

Result of Miko apearance:

47,0 Battleburn
27,8 BobTheDog
18,2 GoC
9,5 Jindra

Result of the two question about Roys fall

69,3 ADD V Junior
-12,0 ADD BobTheDog
-69,3 ADD Gashad
-73,4 ADD GoC
-102,2 ADD Ave
-102,2 ADD Battleburn
-166,0 ADD Jindra34


Active questions:

Will Roy get resurected before zombification and #480?

The_Rogue_Monk 95/5
jindra34 35/65
Frigs 80/20
Thorfluff 0/100
Reed 35/65
MusScribe 83/17
BobTheDog 55/45
Curunir 70/30
Homer HT 85/15


Will Xykon get to touch the saphire?

Jindra34 79/21
BobTheDog 33/66


Open questions:
Will Tsukiko survive the next comic featuring her?

[BobTheDog]

Tass, you really sure you don't wanna break the Roy resurrection question in two? Perhaps come saturday...

[David Argall]

Question for this weekend?

Will Xykon get to touch the saphire?
A Yes
B No

base 50-50. However, touching here counts being forced to touch [and probably getting blown up]. If we limit get to touch to Xykon disposing of his foes long enough to make a grab at it, that is about a 20% chance.

[Tass]

New questions:

Edit: Closed without any bets :smallannoyed:

[BobTheDog]

Huh, I didn't even SEE the questions up, with all the forum going berserk and all that.

[Tass]

Is Tsukiko going to survive the next comic featuring her?
A: Yes
B: No

[Tolkien_Freak]

B. (10 characters)

[Tass]

B. (10 characters) 10 Characters? I dont understand.

[Albonor]

Is Tsukiko going to survive the next comic featuring her?

A: 65/35

[Xanos]

A: 100 / 0

[Tass]

Betting closed