# General Poker Discussion Poker Forums

## Simple probability question

or track by Email or RSS

#### pokergarden

374 posts
Joined 11/2010

I found a website that states when you are holding a pocket pair the following is true:

Odds/probability of flopping a set or better 8.5 to 1
(or 10.5% chance)
Odds/probability of flopping a set 7.5 to 1
(or 11.8% chance)

Am I missing something or is it impossible for the first percentage to be lower than flopping a set.

#### shuttle

3359 posts
Joined 11/2008

I found a website that states when you are holding a pocket pair the following is true:

Odds/probability of flopping a set or better 8.5 to 1
(or 10.5% chance)
Odds/probability of flopping a set 7.5 to 1
(or 11.8% chance)

Am I missing something or is it impossible for the first percentage to be lower than flopping a set.

The other website is incorrect. As flopping a set or better always happens when we flop a set it follows that pr(flopping set or better) > pr (flopping a set)

#### BaseMetal

2060 posts
Joined 01/2010

I found a website that states when you are holding a pocket pair the following is true:

Odds/probability of flopping a set or better 8.5 to 1
(or 10.5% chance)
Odds/probability of flopping a set 7.5 to 1
(or 11.8% chance)

Am I missing something or is it impossible for the first percentage to be lower than flopping a set.

I suspect the confusion is due to the common problem of odds and probabilities.
Prob = No. of good outcomes/ total number of outcomes
Odds = No. of good outcomes/No of bad outcomes

The usual way of describing set odds is 7.5 to 1, or 7.5:1
This matches up to a probability of 1/8.5 or 1 in 8.5.

The probability of a pair hitting at least a set = 0.118 = 1/8.47
This is equivalent of odds of (8.47 - 1) to 1 against, or approx. 7.5 to 1

I think just about everyone mixes up odds and probabilities from time to time, it's very easily done.

You shouldn't really use both "Odds/probability of flopping a set or better 8.5 to 1" as this is quite confusing. Is it odds or is it probability? The "to 1" does seem to indicate odds more but in this case I think they mean probs!

#### pokergarden

374 posts
Joined 11/2010

Oh right. That makes sense.

HomePoker ForumsGeneral Poker Discussion → Simple probability question