You're asking six year old level math questions now

It is beginners section aftetall right? I'm a beginner

I came to a conclusion that odds of same event cannot be added up. They can be flipped (in favour/against), but can never be added up to equal 1 or 100% - is this correct?

What does this mean? It's possible you are mixing odds offered by a casino with probability.

I can't imagine why you'd want to add odds, but if your really wanted to, it's possible (though it only makes sense if the odds are expressing probabilities as opposed to payouts). However, your method of adding was wrong, even though it happened to get the right result that time.

You can only add fractions with the same denominator, but when the denominators don't match, you can convert them to a common denominator. Odds have a requirement of their own: you can only add odds whose left and right sides add to the same total, for instance 1:3 and 3:1 each total 4, whereas 1:3 and 1:5 have different totals.

When there is a mismatch, you can convert them to a common total. To convert 1:3 and 1:5 to the common total, an easy way would be to multiply the two totals 4 * 6 = 24, so 1:3 becomes 6:18, and 1:5 becomes 4:20. Or, you can observe that 4 and 6 both divide 12 (which is obvious, but if it weren't, you can break each down e.g. 4=2*2 and 6=2*3 so take 2*2*3 = 12).
Then 1:3 becomes 3:9 and 1:5 becomes 2:10

But 3:9 + 2:10 doesn't equal 5:19, it equals 5:7

When adding fractions, you only add the numerators.
When adding odds, you only add the left-hand-sides, and for the RHS you use (Total - LHS).
3:9 and 2:10 each total 12, so for the sum you say 5 : (12-5) = 5:7

You can do all that, or you can simply convert to fractions 1/4 and 1/6 and then, without worrying about matching the denominators or anything, simply add them on your calculator

its fine, I understand now, thank you all

Does anyone have the book Poker Math That Matters? I think I found an error in it and wanted to double check

Post a screengrab of what you think is an error.

Just to say, the images in this series are no longer working due to changes at Photobucket.

Just in case anyone's interested, I've cobbled together a .pdf of the whole series.
Formatting is less than wonderful but at least you get the images.
PM me with an email address and I'll happily send it to you.

Does anybody know how to average same statistics based on different sample sizes from different occasions?

Let's say someone's PFR is 20 after 100 hands, then different session, same person's PFR is 10 after 50 hands.

Is his average PFR still gonna be 15?

PS:
nvm, I got it wrong me

No, the average must be weighted by the sample size. in this case, multiply 20 by 100, add 10 times fifty, and then divide by the total 150 hands. Your new average should be 16.66.

Riiiiight

So could the formula for multiple sessions look like this?:

ss - session statistic
sh - session hands
th - total hands

[ (ss*sh) + (ss*sh) ] / th =

You are making it unnecessarily complicated. Just divide the total number of hands raised by the total number of hands played. No need to get into any percentages before that.

Session 1: 100 played, 20 raised. Session 2: 50 played, 5 raised. (20+5)/(100+50) = 25/150 = 1/6 = 16.67%.

Hi madlex,

PFR statistic is always displayed as a percentage by a poker HUD and that will be the information I'm gonna try to work with. So it's already been calculated by a HUD.

I also have more then two sessions to average. There's gonna be potentially hundreds of sessions to keep adding on in the long run maybe

Here is my first session of 5 tables to average. I'm trying to get this guy's average PreFlopRaise %

Table1: 162 hands, PFR 33%
Table2: 101 hands, PFR 24%
Table3: 147 hands, PFR 27%
Table4: 168 hands, PFR 20%
Table5: 177 hands, PFR 24%

You know how madlex said just divide the total number of hands raised by the total number of hands played? Do that.

But I don't have information about hands raised. Just percentages of raising.
I could ofc revert percentages into hands but is that not more complex?

Table1: 162 hands, PFR 33%
so 33% of handss out of total 162 hands is ~53 hands

Are you not understanding the concept or are you not understanding the algebra?

Just work through an example that you are comfortable with and all will be revealed. For example, suppose I own a movie theater and want to get some idea of the overall percentage of women who attend my cinema.

First day there were a total of 50 customers and 40% were women.
Second day there were a total of 150 customers and 30% were women.

If I want to figure out the percentage of women attending over the two days combined, what should I do?

Maybe both, who knows

I think i understand SpewingIsMyMove's way of doing it, but not the other one

Let's see

[ ( 50 x 40 ) + ( 150 x 30 ) ] : 200 =
[ 2000 + 4500 ] : 200 =
6500 : 200 = 32.5

32.5% women in your theatre over the first 2 days, yes?

Yes, so it seems you understand both the concept and the algebra.

You can now apply this method to the data from your five-table example in post #62. Same principle. Very easy with a calculator.

Are you trying to discern between what a player’s PFR is on average, versus what a player’s PFR is *this* session? If so you are on the edge of making incorrect assumptions about the play of said player that are likely to be just random.

Discerning “lately” from “always” requires lots more math.

ok thanks whosnext

robert_utk, nono, just total average addep up from every session i played and will play