Poker Video: Misc/Other by bellatrix (Micro/Small Stakes)

Math Attacks: Episode One

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Math Attacks: Episode One by bellatrix

Chapter 1 - The topic is meaning of +EV, or making decisions and probability related to them. The homework file for this week is here.

Bellatrix takes you on a journey through The Mathematics of Poker by Bill Chen and Jerrod Ankenman, breaking down each chapter one at at time. Warning - if you haven't figured it out by now, there will be math!

Video Details

• Game:
• Stakes: Micro/Small Stakes
• 37 minutes long
• Posted about 2 years ago

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Cangurino

3 posts
Joined 02/2011

Let A be the event that there are two spades on the flop, B the event that a given player holds two spades. You calculated the probability P(A|B). However, in flushdrawitis we are interested in the opposite conditional probability P(B|A), namely given that the board is two-tone, what is the probability my opponents holds a flush draw.

bellatrix

826 posts
Joined 12/2007

Let A be the event that there are two spades on the flop, B the event that a given player holds two spades. You calculated the probability P(A|B). However, in flushdrawitis we are interested in the opposite conditional probability P(B|A), namely given that the board is two-tone, what is the probability my opponents holds a flush draw.

Yeah, you are correct. Somehow I went through this backwards.

Should be 11 choose 2 / 47 choose 2 if we don't have one of the suits in our hand (or 10 choose 2 / 47 choose 2 if we do)

Bad example to make that "flushdrawitis" point. But a good example on how to calculate conditional probablities, sigh.

bellatrix

826 posts
Joined 12/2007

The equation on the right holds for independent events as well; in this case, P(B|A) = P(B).

That's right!
Didn't feel like I should mention it, but you are certainly correct

bellatrix

826 posts
Joined 12/2007

So the expected value is not a characteristic of the probability distribution but one of the random variable you implicitly define.

The probability distribution acts as a sort of weighting function. It still needs to be multiplied by each possible outcome.

amussic

7 posts
Joined 06/2010

is this series really important for poker player, because I have some problems with understanding this formulas...

bellatrix

826 posts
Joined 12/2007

is this series really important for poker player, because I have some problems with understanding this formulas...

I feel that I can't answer the question, because I am biased.
Is this series absolutely necessary to crush the games? Of course not.
But I do feel it will give you some valuable insights on how to approach the game.

OranRai

59 posts
Joined 02/2010

Hi,
We could say that :

Probality that one event happens = Number of favorable events / All possible events

Example :
Probabilty to have 2 or 6 by launching a die is : 2 (2 favorable numbers among 6) / 6 (the numbers of the dice) = 2/6
Regards

OranRai

59 posts
Joined 02/2010

Hi,
I dont know if already done, we have to mention that the sum of p_i is 1 = 100 %
Regards

OranRai

59 posts
Joined 02/2010

Hi,
It will be useful to explain thru example the Slansky bucks concept
Regards

bellatrix

826 posts
Joined 12/2007

Hi,
It will be useful to explain thru example the Slansky bucks concept
Regards

I thought I did that later in the episode?

stanmore

3509 posts
Joined 03/2010

6 people in our study group... Six different answers for the Lotto question in the homework.

Go TEAM!

bellatrix

826 posts
Joined 12/2007

6 people in our study group... Six different answers for the Lotto question in the homework.

Go TEAM!

I had several answers in the beginning, too. Just send me an e-mail (bellatrix@deucescracked.com) with one of your solutions and I'll be sure to get you mine. Good luck, mates!

stanmore

3509 posts
Joined 03/2010

Cheers!

We video-conferenced and winnowed our answers down to one or two, so shouldn't be too bad.

PS on a highly unrelated note my apartment building faces north so I can see Bellatrix when I head out to work at midnight. Except I'm in the Southern Hemisphere and Orion appears upside down to me! So she's on the bottom-left, rather than the top-right.

bellatrix

826 posts
Joined 12/2007

I can see Bellatrix when I head out to work at midnight. So she's on the bottom-left, rather than the top-right.

FYP. Makes it more cryptic. ;-)

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