Math experts please pm me.

[Albert Pujols]

Thanks.

[SamsNCharge99]

don't have PMs, but currently a math major at school

maybe I can help

[Albert Pujols]

Trying to figure out if I was cheated or just had unbelievably bad variance. Lost $893 after playing $7155 worth of $5 blackjack. Perfect basic strategy with surrender.

[Justin7]

Trying to figure out if I was cheated or just had unbelievably bad variance. Lost $893 after playing $7155 worth of $5 blackjack. Perfect basic strategy with surrender.

Here is a napkin solution:

rough volatility per bet in BJ is about 1.3 (?). So you are down 893 / 5 / 1.3, or 137 hands.

7155 in volume is 1431 hands. a standard deviation is (again, quick solution assuming p = 0.5) is about 38. On the downside is 19.

137 / 19 is Z - 7.2. Your luck is 7.2 deviations below mean. Is that roughly 1 in 404k?

I would ask for a hand history and have someone review it.

[Justin7]

Er, one other thing. A typical game has a house edge of about 0.5%. 7155 in volume, you should lose roughly 360. So your chance side is 893-360, or 533. 533 / 1.3 / 5 / 19 = 4.3. So now we're ... 1 in 1600? Possible, but fishy enough to ask for a hand history.

[Albert Pujols]

Er, one other thing. A typical game has a house edge of about 0.5%. 7155 in volume, you should lose roughly 360. So your chance side is 893-360, or 533. 533 / 1.3 / 5 / 19 = 4.3. So now we're ... 1 in 1600? Possible, but fishy enough to ask for a hand history.

Expected loss is $36, not $360.

[Flight]

You could also look at W-L record and assume a 50% game, figure out the Z score of the record. Although split/double would skew the W-L because you are playing 2 W's or 2 L's.

Or you could just read what's already been written about the subject.

http://wizardofodds.com/blackjack/appendix4.html

3500 hands, 450 units lost, you are well below .01% (< 1 in 10,000)

I assume this was not an in-person session.

[Flight]

I am of a rare breed though; I see 1 in 10,000 as perfectly reasonable odds of occurring. (ie if this is a website, they probably have hundreds of thousands of sessions per year, so this will happen several times to several players who will almost surely complain. The odds seem so improbable that human psychology comes into play and cause people to say things like "why me?" or "this is impossible!" when it's not impossible; just improbable. You would also expect several players to win $800 over the course of a year)

[Albert Pujols]

I am of a rare breed though; I see 1 in 10,000 as perfectly reasonable odds of occurring. (ie if this is a website, they probably have hundreds of thousands of sessions per year, so this will happen several times to several players who will almost surely complain. The odds seem so improbable that human psychology comes into play and cause people to say things like "why me?" or "this is impossible!" when it's not impossible; just improbable. You would also expect several players to win $800 over the course of a year)

I don't think so. I'm not one that thinks casinos are rigged. But I knew pretty early on that I wasn't playing a fair game.

[Albert Pujols]

I had to keep playing because of rollover. I stopped when it became obvious. Now I just want them to give me my deposit back.