Talk:Odds

How can it be that the chance of you picking a Sunday is 1/6 instead of 1/7? I don't get it - someone explain. — Preceding unsigned comment added by 68.199.229.122 (talk • contribs)

It's one Sunday versus six non-Sundays. The probability that you pick a Sunday is 1/7. That's the same as saying the odds in favor of picking a Sunday is 1/6. More long-windedly, we have

${1/7 \over 1-1/7}={1 \over 6}.$

Nobody said the "chance" that you pick a Sunday is 1/6. It said "odds", not "chance". "Odds" is a precisely definted concept, not the same as "chance" and not the same as "probability", and you have to read its definition.

Michael Hardy 23:41, 18 March 2007 (UTC)

Could someone explain why these are used in probability theory? I mean, I can see that they're used in betting because of hysterical raisins, but why elsewhere? They seem very counterintuitive to me and I always have to convert them to probabilities by doing a:b ==> a/(a+b) except when they are in form 1:x or x:1 where x is large, meaning that I can conveniently convert them to "very (im)probable". I like the naming, though, odd as they are. 82.103.198.180 10:52, 23 July 2006 (UTC)

Odds and probabilities convey the same amount of information, but sometimes one is easier to use than another. Try odds ratio, logit and logistic regression as examples. --Henrygb 20:55, 23 July 2006 (UTC)

They certainly don't seem unintuitive to me. Michael Hardy 23:41, 23 July 2006 (UTC)

Odds are sometimes easier to compute with. For example, it's easier to write a Bayesian filter with odds than with probabilities. The product of two independent sets of odds appropriately combines them as evidence for or against a proposition, while the product of probabilities means something else.

In common usage, bigger odds' seems to mean less likely (a bigger 'against' odd). It also seems to mean the same in betting. [1]. Can somebody confirm this and move it to the article? Andy Rosa 18:22, 28 December 2006 (UTC)

erm

in bookies how come the odds are like 7/2 i never understand what they mean. if it said odds are: win 1/2 that would mean 50% chance right? but more often than not it will be top heavy. someone explain please

Presidential odds

What does it mean when I see a website posting odds for certain candidates, like Guiliani has 9-2 odds, or Hillary Clinton has 7-2 odds? DRosenbach ^{(Talk | Contribs)} 13:55, 27 June 2007 (UTC)

second line is wrong

The very second line of this article is wrong. You go on to say that the probability of picking Sunday is 1/7, which is correct. That would also be expressed as 6:1 odds If the formula m/(m+n) gives probablity of an event with m to n odds, then the probablity in this scenario would be 6/7, which is wrong.

It should say n/(m+n)

Gambling perspective

In gambling, representation of probabilities differs by location - (EU: 1.25, UK: 1/4, US: -400). Juz saying --90.185.76.189 (talk) 20:28, 2 April 2009 (UTC)

What?

Starting an article with a mathematical equation is not the best way to inform people. Can we have some "plain speak" for those of us who are math challenged? —Preceding unsigned comment added by 65.23.116.46 (talk) 06:54, 2 May 2009 (UTC)

I believe that the explanation in the article is plainly wrong, and there is no reference. The odds for getting six when throwing a die, (a dice), is 1 to 5, not 1/5. Odds are unnormalized probabilities. The normalizing divisor is the sum of the odds, so the probability for getting six when throwing a die is 1/(1+5), and the probability for not getting six when throwing a die is 5/(1+5). While probabilities are almost never integers, odds are very often integers, and so odds are more easily accepted by nonmathematicians. Bo Jacoby (talk) 19:22, 21 July 2009 (UTC).

References?

I have never come across this way of speaking. On this account if an event were given odds of 1000, it would be considered very likely. However in the UK, "a thousand to one" would refer to a very UNlikely event. This page gives no references as to where exactly this information is coming from. Please supply that information. Incompetnce (talk) 13:36, 3 August 2009 (UTC)

Breaking up "Gambling odds versus probabilities" section

This passage uses a single example to touch on two different issues, which I think would be better addressed in separate sections:

1) The distinctions among the terms "odds","probability", and "chances".
2) The distinction between the odds a bookie posts and (his beliefs about) the true odds of each outcome

Terminology/math errors

"In a 3-horse race, for example, the true chances of each of the horses winning based on their relative abilities may be 50%, 40% and 10%. These are the relative probabilities of the horses winning and are simply the bookmaker's 'odds' multiplied by 100 for convenience."

1) I think 50%, 40%, 10% can(must?) be called probabilities of the horses winning (not "relative probabilities"), since they represent the probability of that horse winning out of all possible outcomes, as opposed to the ratio between the probabilities of any two of the horses winning.

2) A more vital point: the percentages given are the probabilities [put in decimal form and] multiplied by 100, not the odds multiplied by 100.

Probability of horse #1 winning is 1/2, i.e, .5, i.e., 50%.

Probability of horse #2 winning is 2/5, i.e. .4, i.e., 40% etc.

Odds of horse #2 winning are 2:3, b/c if they have a 40% chance of losing, they have a 60% chance of winning, so the ratio is 40/60 or 2/3 or 66.67%, although I'm not sure it would really mean anything coherent to say "the odds of horse 2 winning are 66.67%".

3) In the rest of the passage, I believe the odds of each horse winning are all stated backwards, meaning they actually give the odds of each horse losing. Saying the probability of a horse winning is 60% represents odds of 6:4, not 4:6.

I'm a new editor and only a dabbler in probability, so worry that I'm making errors and/or am unable to explain my points clearly, so wanted to get some second opinions before I put anything into the article. Thanks!