The Theory Of Poker: anyone checked the probabilities?

[Roy__Batty]

I tried to check the probs given by Sklansky and, in many cases, i don't get the same figures as him, although some calculations seem to be quite easy.
Example: sheet 40
Stud 7, you start with 6c 7d 8s 9h and you see 8 other cards.
If, among these 8 cards, there is no 5 or ten, what are the chances to get a straight?
Sklansly gives a 49,8% chance.
I get 48,8%.
Maths look quite easy there.
Does anyone know if sklanlsky actually made the calculations or just used simulations (even with simulations, the 1% difference seems high).
Any help appreciated!

[Andy B]

Well, lessee, the probability that you don't make the straight is 32/40 * 31/39 * 30/38, which I make to be .502. The probability that you do make the straight is 1-.502, or .498. So the 49.8% figure is right, unless both Sklansky and I have somehow screwed up, which I find somewhat unlikely. [img]/images/graemlins/grin.gif[/img]

That said, say it was only 48.8%. Does that change how you're going to play the hand one iota?

[Roy__Batty]

ho....
looks like i made some error in my calc.
What i made: Prob[no straight]=C(32;3)/C(40;3) which obviously is the same as you.
C(32;3)=4960
C(40;3)=9880, which i wrote as 9680 in my results!!! That makes the 1% difference.
Will check my calculations before posting...promised. [img]/images/graemlins/blush.gif[/img]
Thanks Andy!