Does anyone understand this twodimes discrepency?

[Mizzles]

What am I missing here? Here are 2 similar hands plugged into twodimes with completely different results ??? In both cases person holding pocket pair has flopped open end straight vs. opponent flopping two pair. Why are the win/lose results not even close? Aren't the number of outs for the PP the same in both?



HANDS: 8h 7s vs. 9h 9s
BOARD: 7h 8d Tc

cards win %win lose %lose tie %tie EV

7s 8h 498 50.30 476 48.08 16 1.62 0.511
9s 9h 476 48.08 498 50.30 16 1.62 0.489

HANDS: 9h Ts vs. 8h 8s
BOARD: 7h 9d Tc

cards win %win lose %lose tie %tie EV

Ts 9h 635 64.14 339 34.24 16 1.62 0.649
8s 8h 339 34.24 635 64.14 16 1.62 0.351

[bigpooch]

Think about a running pair:

In the first case, 99 wins on a running pair, such as deuces
on the turn and river.

In the second case, 88 doesn't win on a running pair.

[Mizzles]

Does a running pair really account for that much of a difference?

[bigpooch]

Doesn't have to be just a running pair; the board could also
pair up on the "other rank" on the flop to counterfeit
bottom two pairs.

[pzhon]

In the first example, the player with 99 has 13 outs, including any ten. Tens over nines beats tens over eights.

In the second exmple, the player with 88 has 10 outs, as a 7 is not an out. Tens over nines beats eights over sevens.

[AaronBrown]

The 16 ties are a third card to match the pocket pair (2 ways) and a card that completes the stright (8 ways). That's the same in both.

There are 635 - 498 = 137 hands that win for T9 but not 87. Bigpooch found most of them. There are 7 ranks we have not seen at all and don't make straights, each one can pair 6 ways, so that's 42 hands. Also you can pair the T or 7 (whichever does not give the two pair a full house, 3 ways) and combine it with any card 2-5 or Q-A (28 cards). 3 x 28 = 84. 84 + 42 = 126.

The remaining 11 boards give both player full houses. You can give a third card to the pocket pair (2 ways) and also pair one of the board cards that paired the two-pair hand (4 ways). That's 8. Or you can make the other card on the board (the 7 or the T) trips in 3 ways.