What are odds for Set over Set on flop ??

[karr2242]

Hey all, I've been playing a bunch of NL25 recently, and have experienced set over set (ex: board 3 Q K , when i have 333 and another player has QQQ) like 3 times in a couple weeks. What are the odds for set over set bad beat on the flop?
I'm guessing you'd have to calculate odds of your opponent having a pp, and then calculate the odds of hitting a set using only 2 flop cards. Any help would be greatly appreciated. Odds of flopping a set while a player hits a higher set (or any set)?

Thanks
MasterTrav

[RiverTheNuts]

well any pocket is 3/51.. odds of 2 people having different pockets at a full table (10) is 10*(52/52)*(3/51)*(48/50)*(3/49) ... I think... around 1 in 29 hands

So you take 1/29 and you need both of your 2 outters to come... 3*(1/29)*(2/48)*(2/47) = 1 in 5450ish hands

I dont think that is right, because the multiplying by 10 people and 3 cards I dont think is correct math, but it should get you pretty close

[binions]

[ QUOTE ]
Hey all, I've been playing a bunch of NL25 recently, and have experienced set over set (ex: board 3 Q K , when i have 333 and another player has QQQ) like 3 times in a couple weeks. What are the odds for set over set bad beat on the flop?
I'm guessing you'd have to calculate odds of your opponent having a pp, and then calculate the odds of hitting a set using only 2 flop cards. Any help would be greatly appreciated. Odds of flopping a set while a player hits a higher set (or any set)?

Thanks
MasterTrav

[/ QUOTE ]


Assuming you have a pocket pair at a 9 man table, then preflop, there are 73 pairs left and 1225 possible starting hands. The chance at least one other person has a pair is one minus the chance no one else has a pair

1-(1152/1225)^8 = 38.8% at least someone else has a pair

If you have pair, what's the chance of flopping a set if one other pocket pair also flops a set?

48*47*46/3*2*1 = 17296 possible flops assuming 1 other player has a pair.

They flop a set when you do with a flop of Ssy where S is your set card, s is their set card, and y is one of the remaining cards in the deck that doesn't make you or them quads.

There are 2 S cards, 2 s cards and 44 other cards in the deck. 2*2*44 = 176/17296 = 1.02%

So, when you start with a pair, you will find yourself with a set vs. another set on the flop 0.4% (rounded) of the time, or 252:1.

Of course, you start with a pair only once in 17 hands, so the odds of set over set on the flop happening for any particular hand is 4304:1

Assuming live play at 30 hands an hour, this should occur every 144 hours of play or so. It will happen more often on the net, depending on the amount of multitabling.

Whether you have overset or underset depends on your starting pair. With 22, you will always have underset. With AA, you will always have overset. With the others, here are the odds against being underset:

KK 1/12 or 11:1
QQ 2/12 or 5:1
JJ 3/12 or 3:1
TT 4/12 or 2:1
99 5/12 or 7:5
88 6/12 or 1:1
etc.