How likely is likely?

[Cascade]

If I had a better than even chance I would say i would probably win.

 

I might qualify likelihoods in that range in some way from probably and almost certain to probably but could easily lose etc

[dburn]

Idle speculation prompted by the previous three posts prompted these thoughts:

 

Suppose A, B, C and D enter a dice-tossing tournament consisting of two knock-out rounds.

 

B, C and D are armed only with regular cubes whose faces are numbered from 1 to 6, but A has got a regular octahedron with faces numbered from 1 to 8.

 

An octahedral dice (yes, I know what the singular is according to the dictionary, but one should never say "die") will beat a cube with probability 0.642857143 (this is equal to 9/16 + [9/16*1/7], and if you don't know why it should be equal to that, you should study the works of Jeff Rubens until you do).

 

Who is most likely to win the tournament? Why, A of course. Is A likely to win the tournament? No - he will do so only with the above probability squared, which is less than one half. So, even within a very small range of possibilities, that which is most likely to happen is unlikely to happen.

 

Should the lawmakers have used the word "likely" in Law 69B2? Probably not.

[gordontd]

Imagine that you are playing a head-to-head match against team A tomorrow. You rate your opponents as significantly worse than your team. In probability terms, you rate your probability of winning the match as 75%.

 

Imagine that you are also playing a head-to-head match against team B the day after tomorrow. You rate these opponents as almost, but not quite, as good as your team. In probability terms, you rate your probability of winning as 51%.

 

If I ask you if you are going to win your match against team A tomorrow, you might well answer: "Probably".

 

If I ask you if you are going to win your match against team B the day after tomorrow, you might well answer: "Maybe", "Possibly" or "About 50-50". But you would not say "Probably", would you?

If I rated our chances as 55% and you asked me if we are likely to win (it's "likely" that's used in the wording, not "probably") I'd say yes.

[Cascade]

If I rated our chances as 55% and you asked me if we are likely to win (it's "likely" that's used in the wording, not "probably") I'd say yes.

 

Exactly you are more likely than not to win.

[gnasher]

Do "It is likely that I will win a trick", "I am likely to win a trick" and "I will likely win a trick" all mean the same thing?

[axman]

Idle speculation prompted by the previous three posts prompted these thoughts:

 

 

Should the lawmakers have used the word "likely" in Law 69B2? Probably not.

 

Where it comes to do-overs, the specification of 'likely' is dubious; unless, of course, the desire is an immense amount of litigation and dissatisfaction.

[suprgrover]

An octahedral dice (yes, I know what the singular is according to the dictionary, but one should never say "die") will beat a cube with probability 0.642857143 (this is equal to 9/16 + [9/16*1/7], and if you don't know why it should be equal to that, you should study the works of Jeff Rubens until you do).

 

Isn't this probability just 9/16? That's what I get when I either do the math or run a lot of trials. (Your fundamental point still holds, of course.)

[WellSpyder]

Isn't this probability just 9/16? That's what I get when I either do the math or run a lot of trials. (Your fundamental point still holds, of course.)

I think it depends on what you do if the match is a tie. dburn assumes you toss the dice again, with a further 9/16 chance of the octahedron winning and a 1/8 chance of another tie....

[lamford]

Interestingly, Law 69B2 would not appear to allow the TD to transfer a trick which he is 100% sure would have been won by the non-claiming side: "would definitely have won" does not appear to be a subset of "would likely have won" and 69B1 seems to refer to tricks which had been completed before the claim. But I may have misunderstood; I can't believe that this is what the lawmakers intended.

But the claiming side cannot accept the trick either under 79A2: "A player must not knowingly accept either the score for a trick that his side did not win or the concession of a trick that his opponents could not lose." If you are right, therefore, the trick will be unallocated - indeed I could find nothing in the Laws to indicate that a trick had to be won by one side or other, or that the total number of tricks must total 13! I expect there is something there if I look hard enough.

[bluejak]

A has got a regular octahedron with faces numbered from 1 to 8.

I always wanted one of those for Backgammon. It always seemed silly to me that you do not have a side 1 on the doubling cube. Having played a few 64 games and one at 128 I feel eight faces for the doubling "cube" numbered 1, 2, 4, 8, 16, 32, 64, 128 far more sensible.

 

:ph34r:

 

The problem with "likely" is simple: it means different things in different contexts, and even different things to different people. Perhaps the only real solution is to get an interpretation from a relevant authority but let us see what we can do.

 

Law 12C1E includes the following wording "The score assigned in place of the actual score for a nonoffending side is the most favourable result that was likely had the irregularity not occurred." This means that, in the ACBL, it is important to know what "likely" means Furthermore, this was part of Law 12C2 used worldwide under earlier Law books. How does the ACBL interpret 'likely', and did the rest of the world interpret 'likely' for this Law?

 

I have been told that there is an interpretation in the ACBL that likely is 1 in 3, while at all probable [Law 12C1E2 for the offenders] is 1 in 6. Many years of discussion on newsgroups and forums, talking to my American friends including top TDs, and sitting on and commenting on ACBL ACs have convinced me it may be an official interpretation but it is certainly not followed. The actual usage is probably closer to 1 in 5 for likely and 1 in 10 for at all probable. The EBU came up with an approach that tended to mirror this.

 

So, how about 1 in 5 for likely? I suppose it means "a reasonable likelihood". But as others have pointed out, if a player said "I am likely to win this match" he probably means he has at least a 6 in 10 chance of winning. Maybe it is the difference in wording, "that was likely" is a lower likelihood, so perhaps Law 12C is a red herring.

 

Perhaps we should look at logic and fairness, not always the best approach in interpreting the Law book. :rolleyes: What would we expect this Law to mean?

 

Agreement with a claim or concession (see A) may be withdrawn within the Correction Period established under Law 79C .... if a player has agreed to the loss of a trick that his side would likely have won had the play continued.

Suppose we have this position where a player would have won a trick a certain percentage of the time. What does this Law feel like? Should we give him the trick if he would have won it 15% of the time? 25%? 35%? 45%? 55%? 65%? 75%? 85%?

 

My feeling is that 55% accords with th feel of this Law. What do you think?

[suprgrover]

I think it depends on what you do if the match is a tie. dburn assumes you toss the dice again, with a further 9/16 chance of the octahedron winning and a 1/8 chance of another tie....

 

Yes, that's exactly it. Carry on.

[RMB1]

I always wanted one of those for Backgammon. It always seemed silly to me that you do not have a side 1 on the doubling cube. Having played a few 64 games and one at 128 I feel eight faces for the doubling "cube" numbered 1, 2, 4, 8, 16, 32, 64, 128 far more sensible.

 

Where I learnt backgammon (at the feet of John Conway), we had a second hexahedral cube for the next six powers of 2.

[jallerton]

The problem with "likely" is simple: it means different things in different contexts, and even different things to different people. Perhaps the only real solution is to get an interpretation from a relevant authority.

 

I agree with this, at least for the 2007 Laws. For the next version of the Laws, it would be highly desirable if all needlessly ambiguous terms such as this could be properly defined.

 

Perhaps we should look at logic and fairness, not always the best approach in interpreting the Law book. :rolleyes: What would we expect this Law to mean?

 

Suppose we have this position where a player would have won a trick a certain percentage of the time. What does this Law feel like? Should we give him the trick if he would have won it 15% of the time? 25%? 35%? 45%? 55%? 65%? 75%? 85%?

 

My feeling is that 55% accords with th feel of this Law. What do you think?

 

My feeling is that the TD should rule by considering whatever he thinks the Law actually says; without any further definition or guidance, the TD has to make this interpretation himself.

[nigel_k]

The problem with "likely" is simple: it means different things in different contexts, and even different things to different people.

Absolutely correct.

 

This is a language problem not a maths problem, so words can mean different things depending on context. Here there is not enough context to clearly indicate which meaning is correct. But we have to try to use a combination of what context we have and what makes sense generally, rather than just relying on the dictionary definition of a word in isolation.

[blackshoe]

Law 12C1E includes the following wording "The score assigned in place of the actual score for a nonoffending side is the most favourable result that was likely had the irregularity not occurred." This means that, in the ACBL, it is important to know what "likely" means Furthermore, this was part of Law 12C2 used worldwide under earlier Law books. How does the ACBL interpret 'likely', and did the rest of the world interpret 'likely' for this Law?

 

I have been told that there is an interpretation in the ACBL that likely is 1 in 3, while at all probable [Law 12C1E2 for the offenders] is 1 in 6. Many years of discussion on newsgroups and forums, talking to my American friends including top TDs, and sitting on and commenting on ACBL ACs have convinced me it may be an official interpretation but it is certainly not followed. The actual usage is probably closer to 1 in 5 for likely and 1 in 10 for at all probable. The EBU came up with an approach that tended to mirror this.

 

So, how about 1 in 5 for likely? I suppose it means "a reasonable likelihood". But as others have pointed out, if a player said "I am likely to win this match" he probably means he has at least a 6 in 10 chance of winning. Maybe it is the difference in wording, "that was likely" is a lower likelihood, so perhaps Law 12C is a red herring.

 

Perhaps we should look at logic and fairness, not always the best approach in interpreting the Law book. :rolleyes: What would we expect this Law to mean?

 

 

Suppose we have this position where a player would have won a trick a certain percentage of the time. What does this Law feel like? Should we give him the trick if he would have won it 15% of the time? 25%? 35%? 45%? 55%? 65%? 75%? 85%?

 

My feeling is that 55% accords with th feel of this Law. What do you think?

 

I am not surprised that TDs in the ACBL don't follow the ACBL's guidelines. Actually, I'm kinda surprised there are guidelines, since I'd never heard of any, until now.

 

To me, "at all probable" means the probability is greater than zero. "Likely" is harder; I don't really have a problem with 1 in 5, or with 55%, depending how you interpret the words. Not much help, I suppose. :P

[AlexJonson]

Perhaps as well as having a 'Change the Laws' forum, we could have an 'Interpret the Laws forum'.