Blackjack probability question for BJ players

[pokeraddict]

I am not as good at figuring out math when it comes to blackjack so I ask that those who are great at it help me.

I played blackjack at a place I felt was fishy because the dealer kept having 20 or blackjack dealt so I decided I would come back again later and start to track the play.

In session 1 I played 230 hands I counted each time both of us were dealt 20 or BJ. In 230 hands the dealer had 16 blackjacks, I had 4. The dealer dealt himself 29 20's, I was dealt 20 14 times. I emailed and asked for the logs and got them very quickly.

In session 2 I played exactly 200 hands. The dealer had 14 blackjacks, I had 2. The dealer was dealt 20 32 times, I was dealt 20 11 times. I have emailed the casino and asked for logs to this session repeatedly and have yet to have a response.

Obviously the results are very screwed up. Do I have enough hands to make this mathematically useful? Do I need more hands? What are the probabilites of the above results? Thank you in advance.

[pokeraddict]

I should include that in the 2 sessions combined of 430 hands I lost 25 units. The number of busts seemed normal and my number of double and splits wins seemed normal.

[GrandMaster]

The probability of getting 6 or fewer BJ's in 430 hands is between 0.00011 (1 deck) and 0.00014 (8 decks). The probability of getting 30 or more BJ's in 430 hands is between 0.024 (8 decks) and 0.029 (1 deck).

When you talk about dealing 20s, do you mean just the first two cards?

[pokeraddict]

Yes I only counted the first 2 cards. I counted A9 or two 10 value cards. I already assume the dealer will get more 20's since he will draw more often thus making that kind of useless info.

[Clayman]

The probability of getting 6 or fewer BJ's in 430 hands is between 0.00011 (1 deck) and 0.00014 (8 decks). The probability of getting 30 or more BJ's in 430 hands is between 0.024 (8 decks) and 0.029 (1 deck).

Would you agree that, given 36 BJ's, the odds of the player getting 6 or fewer is about 1 in 28,700?

It's not like the total number of BJ's is that far off.

Obviously losing 25 units in 430 hands ain't no big deal. Wish that was all I lost yesterday.

[GrandMaster]

The probability of being dealt 25 or fewer 20's in 430 hands is between 0.00036 (8 decks) and 0.00078 (1 deck). The probability of being dealt 61 or more 20's in 430 hands is between 0.00041 (1 deck) and 0.00082 (8 decks).

If you count BJ's and 20's together, it gets worse. The probability of being dealt 31 or fewer BJ's or 20's in 430 hands is between 0.00000024 (8 decks) and 0.00000048 (1 deck). We are talking about probabilities between 1 in 4 million and 1 in 2 million. The probability of being dealt 91 or more BJ's or 20's in 430 hands is between 0.00047 (1 deck) and 0.00082 (8 decks).

The results are indeed very suspicious. Would you share with us what software it was, or at least PM me if you don't want to make it public?

[eek]

A BJ occurs about once in every 21 hands.

[pokeraddict]

I pm'd the casino where this game took place to Grandmaster. For now I do not wish to start trouble, especially because they are a sportsbook and I have NFL futures on who will win Superbowl, one team I bet has a great chance as a 35-1 underdog so I dont want to start public trouble.

Should I email them this thread and ask them to explain how my 2 tracked sessions were possible? Should I go back and get more hands (betting $1 a hand now) to make it more mathmatically useful? I have beaten this game in the past, and I have played many many hours before busting in the past too. The last few sessions just seemed impossible which is why I decided to track it.

[jerseyguy11]

let me guess. is it an one of those EFS carribean processing casinos? such as betonusa.com or silverstarcasino?

[cipher]

I pm'd the casino where this game took place to Grandmaster. For now I do not wish to start trouble, especially because they are a sportsbook and I have NFL futures on who will win Superbowl, one team I bet has a great chance as a 35-1 underdog so I dont want to start public trouble.

Should I email them this thread and ask them to explain how my 2 tracked sessions were possible? Should I go back and get more hands (betting $1 a hand now) to make it more mathmatically useful? I have beaten this game in the past, and I have played many many hours before busting in the past too. The last few sessions just seemed impossible which is why I decided to track it.

I sure as hell wouldn't go back for more of the same. I'd hav't to think that Jersey's guess is a pretty solid one. Have a good one.