Odds Calculation/EV - Need Help

You have to pardon my ignorance but I have some questions that hopefully will help a newbie like me to improve my game.


I have read in the past several posts on odds after the flop and I have also seen some tables on the subject. My problem is more on odds BEFORE the flop. For example, the odds to flop a set is 7.5 to 1. What about flopping trips or 2 pairs? How do you calculate for these? I guess this will help in calling raises in case of getting trapped with marginal hands. How helpful is Mike Petriv's book. Is it worth buying?


What does EV means and how do you calculate for this?


Any help or guidance from the math whiz or experts will greatly be appreciated. Thank you in advance.

http://www.neo-tech.com/poker/part1b.html


Is this page of any help?

EV means expected value. It is the product of a probability of an occurence and the value of that occurence. For example, the lottery pays $1,000,000 and you have a 1 in 5 million chance of hitting. The EV for this would be, $1,000,000/5,000,000 = $0.20 or twenty cents. So buying a lottery ticket for a dollar would have a negative EV, because the cost of the ticket is more than what its expected value is.


When you look at a pot, the pot has so much money in it. You are betting to win that pot. If you stand to win more than the cost of the bet on the average, then that bet has a positive EV.


It's often easier to calculate the odds of something not happening and subtract that from one. For example, here's the odds of the flop not pairing one of your cards (assuming your hole cards are not already paired)


44/50 * 43/49 * 42/48 = 0.676. The odds of pairing are 1 less this, which is 0.324, or about 32.4%.


A word on the above calculation. For the first card of the flop there are 50 cards you don't know about. Of those 50, 44 will not pair one of your two cards. Assuming that happens (neither card is paired), for the second card there are 49 cards left. Of those, there are 43 that will not pair your two cards. And so forth.


Is your question about trips asking the probability of the board pairing and matching one of your hole cards?


The odds of calculating 2 pair is a bit more involved. I'll be happy to post it if you like, but first would like to know if the above makes sense.

Thanks, Tewall. Yes,it does make sense. Again, my question is about odds of flopping trips or two pair with no pair on hand as this will helpful whether to get involve in the flop. Know anything about Mike Petriv's book on odds? thanks again for your help.