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Topic: Satoshi Dice -- Statistical Analysis - page 26. (Read 192889 times)

hero member
Activity: 728
Merit: 500
April 04, 2013, 03:37:20 AM
It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.

The chance is not 0%, but it is very small, perhaps <<0.001%.

Markov chains are more useful when there's a relationship between the states of the system.  In this case, it would be more like "losing 3 in a row changes your chances of winning the next one".  Since we don't have that, you can use regular IID statistics.  

It seems to me that SD could be modelled as a markov chain since the game is stochastic and has a markov property; that is, the outcome of trial B is not dependent on the outcome of trial A (I'm not sure if that's what you meant?). Although the probability of consecutive lessthan1 "successes" is very remote, it is still possible and a probability is associated with it. Given infinite number of trials, its bound to happen and there is no "losing 3 in a row changes your chance of winning the next one" for the markov model because the game has a markov property (or maybe it doesn't?). Maybe I'm misunderstanding the application of markov models, so please correct any errors I've made.

There's nothing stopping you from using Markov chains to model this problem and get a correct answer.  But it would be like using calculus to compute the area of a square.  It works,  but there's simpler ways to do it.

I think this is somewhat a matter of taste. The MCMC method is more intuitive (at least to me, who is no math whiz), and it is easier to modify for input parameters for testing alternative hypotheses (satoshi dice does not work as claimed in some specific way that may be due to interactions between parameters). There is also a psychological factor in that you are more encouraged to go "outside the box" and mess around. And of course, you always get a nice approximation of the actual distribution, even if it is not normal. The tradeoff is cpu time and expenses. It is less limiting when you want to test other assumptions though, IMO.

edit: I thought of another way of putting it. MCMC slowly gives you an answer about the supposed 'square' you are actually measuring, while your method quickly gives an answer about perfect squares. Which is the better approach depends on how perfect the square is you are trying to measure.
hero member
Activity: 504
Merit: 500
April 04, 2013, 03:11:25 AM
You seem very into tracking Satoshi, Doog  Cheesy

I assume you own a large percentage of it?
legendary
Activity: 2478
Merit: 1362
April 03, 2013, 08:43:53 PM
Is there any way to get exact numbers on total bets and total profit on a month by month basis? It is useful so we can see in exact numbers rather than a graph how the site has been growing.
fred, look after the orange line. It's the EV line. Multiplie it by (1/0.019) and you have the volume of bet.

It only appears as a line, I can't get the exact numbers for each whole month, I wanted to do a month by month comparison of turnover and profit.
Check the other image in the topic Wink
hero member
Activity: 784
Merit: 1000
0xFB0D8D1534241423
April 03, 2013, 08:35:09 PM
It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.

The chance is not 0%, but it is very small, perhaps <<0.001%.
Wrong. Let's say you bet 2 BTC once on the 50/48.1 address. There are only two options:
The house gains 2 BTC (100%)
The house loses nearly 2 BTC (98.1%)
newbie
Activity: 49
Merit: 0
April 03, 2013, 04:50:34 PM
Looks like 1PVkEnfTXD5uHeWZSGeXqGdTZ44KAeZsgV is the new guy to watch, doing mass 20x bet txns all over the board.
newbie
Activity: 56
Merit: 0
April 03, 2013, 04:07:16 PM
Is there any way to get exact numbers on total bets and total profit on a month by month basis? It is useful so we can see in exact numbers rather than a graph how the site has been growing.
fred, look after the orange line. It's the EV line. Multiplie it by (1/0.019) and you have the volume of bet.

It only appears as a line, I can't get the exact numbers for each whole month, I wanted to do a month by month comparison of turnover and profit.
legendary
Activity: 2478
Merit: 1362
April 03, 2013, 04:01:11 PM
Is there any way to get exact numbers on total bets and total profit on a month by month basis? It is useful so we can see in exact numbers rather than a graph how the site has been growing.
fred, look after the orange line. It's the EV line. Multiplie it by (1/0.019) and you have the volume of bet.
newbie
Activity: 56
Merit: 0
April 03, 2013, 03:57:14 PM
Is there any way to get exact numbers on total bets and total profit on a month by month basis? It is useful so we can see in exact numbers rather than a graph how the site has been growing.
legendary
Activity: 2940
Merit: 1333
April 03, 2013, 03:10:33 PM
It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.

The chance is not 0%, but it is very small, perhaps <<0.001%.

I think you may have misunderstood.  If after 1 bet the house has a profit, it's a 99.5% profit (0.5% is returned to the player).  It's never a 1.9% profit.

Quote
Total of 47 bets unaccounted for.

Results: 2013-Apr-03 11:51am (up to block 229527)

   Address  Target   Should Win |    #Bets |        Win        |   Lose  | Refunds |   BTC In   |  BTC Out   |  Refund  |   Profit  |   RTP 
----------------------------------------------------------------------------------------------------------------------------------------------
 1dice1e6p       1      0.00002 |   117399 |       3 (0.00003) |  115561 |    1835 |    1418.85 |    3841.57 |   141.67 |  -2422.71 | 270.751
 1dice1Qf4       2      0.00003 |     6851 |       0 (0.00000) |    6299 |     552 |     111.13 |       0.14 |    22.23 |    110.99 |   0.131
 1dice2pxm       4      0.00006 |     8885 |       1 (0.00012) |    8413 |     471 |     136.37 |     160.10 |    14.54 |    -23.73 | 117.403
 1dice2vQo       8      0.00012 |    15522 |       5 (0.00033) |   15028 |     489 |     304.80 |     432.37 |    10.11 |   -127.57 | 141.856
 1dice2WmR      16      0.00024 |    16464 |       1 (0.00006) |   16000 |     463 |     566.01 |       5.40 |    22.13 |    560.60 |   0.956
 1dice2xkj      32      0.00049 |    23419 |      11 (0.00048) |   22992 |     416 |    1367.75 |    1537.62 |     1.45 |   -169.87 | 112.420
 1dice2zdo      64      0.00098 |    26231 |      32 (0.00124) |   25703 |     496 |    1922.80 |    1521.20 |    55.91 |    401.60 |  79.114
 1dice37Ee     128      0.00195 |    20749 |      38 (0.00187) |   20241 |     470 |    2379.58 |    1562.89 |    48.42 |    816.68 |  65.679
 1dice3jkp     256      0.00391 |    25893 |     113 (0.00443) |   25375 |     405 |    5996.58 |    8653.62 |    13.25 |  -2657.04 | 144.309
 1dice4J1m     512      0.00781 |    37032 |     296 (0.00815) |   36007 |     729 |    8286.23 |    6899.00 |    10.13 |   1387.22 |  83.259
 1dice5wwE    1000      0.01526 |   130886 |    1973 (0.01514) |  128348 |     565 |   40990.30 |   36083.16 |     2.22 |   4907.14 |  88.029
 1dice61SN    1500      0.02289 |    25466 |     581 (0.02315) |   24520 |     365 |    7961.39 |    8558.13 |    15.12 |   -596.73 | 107.495
 1dice6DPt    2000      0.03052 |    84015 |    2570 (0.03074) |   81042 |     403 |   40958.39 |   36633.46 |     9.39 |   4324.92 |  89.441
 1dice6gJg    3000      0.04578 |    30057 |    1367 (0.04621) |   28217 |     473 |    9808.39 |   10627.78 |    25.34 |   -819.38 | 108.354
 1dice6GV5    4000      0.06104 |    36081 |    2216 (0.06211) |   33462 |     403 |    7723.23 |    7513.56 |    31.39 |    209.66 |  97.285
 1dice6wBx    6000      0.09155 |    50262 |    4569 (0.09179) |   45206 |     487 |   16789.73 |   18399.76 |     7.43 |  -1610.02 | 109.589
 1dice6YgE    8000      0.12207 |   196469 |   24023 (0.12261) |  171903 |     543 |   96113.87 |   94971.36 |   100.62 |   1142.50 |  98.811
 1dice7EYz   12000      0.18311 |   104377 |   18973 (0.18280) |   84819 |     585 |  175335.89 |  176243.30 |  3315.05 |   -907.40 | 100.518
 1dice7fUk   16000      0.24414 |   270168 |   65844 (0.24426) |  203719 |     605 |  372802.77 |  358817.24 |  2322.58 |  13985.52 |  96.249
 1dice7W2A   24000      0.36621 |   263772 |   96786 (0.36779) |  166368 |     618 |  590251.02 |  582124.88 |  1013.34 |   8126.13 |  98.623
 1dice8EMZ   32000      0.48828 |  1167655 |  569067 (0.48810) |  596824 |    1764 |  903486.61 |  885558.38 |  2925.34 |  17928.23 |  98.016
 1dice97EC   32768      0.50000 |   652546 |  325402 (0.49966) |  325839 |    1305 |  679635.59 |  662940.30 |  6521.88 |  16695.28 |  97.543
 1dice9wcM   48000      0.73242 |   371003 |  272221 (0.73522) |   98039 |     743 |  307390.07 |  300293.47 |  6172.23 |   7096.60 |  97.691
 1dicec9k7   52000      0.79346 |    83238 |   65666 (0.79445) |   16990 |     582 |   64156.04 |   62745.47 |  1187.78 |   1410.56 |  97.801
 1dicegEAr   56000      0.85449 |    74192 |   63010 (0.85675) |   10535 |     647 |   81314.33 |   80528.56 |   400.81 |    785.76 |  99.034
 1diceDCd2   60000      0.91553 |   116106 |  105780 (0.91625) |    9669 |     657 |   74182.51 |   73131.53 |     0.97 |   1050.97 |  98.583
 1dice9wVt   64000      0.97656 |    19248 |   17566 (0.97964) |     365 |    1317 |   24733.69 |   24319.01 |   240.51 |    414.67 |  98.323
----------------------------------------------------------------------------------------------------------------------------------------------
           small (bets < 4 BTC) |  3854007 | 1583822           | 2252090 |   18095 |  811433.98 |  797411.52 |   286.73 |  14022.46 |  98.272
            big (bets >= 4 BTC) |   119979 |   54292           |   65394 |     293 | 2704690.03 | 2646691.88 | 24345.21 |  57998.15 |  97.856
----------------------------------------------------------------------------------------------------------------------------------------------
                                |  3973986 | 1638114           | 2317484 |   18388 | 3516124.02 | 3444103.40 | 24631.95 |  72020.61 |  97.952
----------------------------------------------------------------------------------------------------------------------------------------------

SD Profit before fees:      72020.61453961 BTC (2.048%)
Cumulative Fees Paid:        3184.91817500 BTC
SD Profit after fees:       68835.69636461 BTC (1.958%)
Pending Liabilities:           -0.52469045 BTC
Final SD Profit:            68836.22105506 BTC (1.958%)
Profit This Month:            993.29448744 BTC
----
Since Satoshi Dice started, there have been:
Blockchain Tx: 12577501  :  SatoshiDice Tx:  7301854  (58.1%)
Blockchain MB:   5452.9  :  SatoshiDice MB:   3009.1  (55.2%)



legendary
Activity: 1428
Merit: 1093
Core Armory Developer
April 03, 2013, 02:15:58 PM
It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.

The chance is not 0%, but it is very small, perhaps <<0.001%.

Markov chains are more useful when there's a relationship between the states of the system.  In this case, it would be more like "losing 3 in a row changes your chances of winning the next one".  Since we don't have that, you can use regular IID statistics.   

It seems to me that SD could be modelled as a markov chain since the game is stochastic and has a markov property; that is, the outcome of trial B is not dependent on the outcome of trial A (I'm not sure if that's what you meant?). Although the probability of consecutive lessthan1 "successes" is very remote, it is still possible and a probability is associated with it. Given infinite number of trials, its bound to happen and there is no "losing 3 in a row changes your chance of winning the next one" for the markov model because the game has a markov property (or maybe it doesn't?). Maybe I'm misunderstanding the application of markov models, so please correct any errors I've made.

There's nothing stopping you from using Markov chains to model this problem and get a correct answer.  But it would be like using calculus to compute the area of a square.  It works,  but there's simpler ways to do it.
newbie
Activity: 29
Merit: 0
April 03, 2013, 02:07:11 PM
It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.

The chance is not 0%, but it is very small, perhaps <<0.001%.

Markov chains are more useful when there's a relationship between the states of the system.  In this case, it would be more like "losing 3 in a row changes your chances of winning the next one".  Since we don't have that, you can use regular IID statistics.   

It seems to me that SD could be modelled as a markov chain since the game is stochastic and has a markov property; that is, the outcome of trial B is not dependent on the outcome of trial A (I'm not sure if that's what you meant?). Although the probability of consecutive lessthan1 "successes" is very remote, it is still possible and a probability is associated with it. Given infinite number of trials, its bound to happen and there is no "losing 3 in a row changes your chance of winning the next one" for the markov model because the game has a markov property (or maybe it doesn't?). Maybe I'm misunderstanding the application of markov models, so please correct any errors I've made.
legendary
Activity: 1428
Merit: 1093
Core Armory Developer
April 03, 2013, 12:15:51 PM
Perhaps I should have asked instead, how many trials would it take to theoretically reach 1.9% with a 95% confidence interval?

Well alright.  Now I can say "I don't know" instead of "your question sucks" Smiley

It's affected a lot by the big bets.  The profit from thousands of small bets can be wiped out by a single lucky big bet (and vice versa).
The question should have one more number. It should be phrased "95% chance that the house edge will be within 1.89-1.91%" or similarly. The size of the acceptable error there will greatly influence the result.
And... I don't remember how to do a problem like that Cry It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.


I think it can be assessed using Markov chains. Meni Rosenfeld's analysis of PPS pool bankruptcy probabilities (AoBPMRS, Appendix c) examines a similar problem and uses a Markov chain model. I haven't studied them, maybe someone else more familiar with Markov chains could do the analysis.

Markov chains are more useful when there's a relationship between the states of the system.  In this case, it would be more like "losing 3 in a row changes your chances of winning the next one".  Since we don't have that, you can use regular IID statistics.   

The way I wrote the script that dooglus is using right now, is taking advantage of the fact that for a sum of random variables, you can just add their expected values, and add their variances.  Square-root the resulting variance ot get the standard-deviation.  The result will be a mean and std-dev, which you can use to compute a 3-sigma bounding box (or 2-sigma, if you want 95% confidence).

For binary systems like this (win or lose), you'd "normally" use different equations, but this construction is accurate as the number of trials gets large.  SatoshiDice qualifies.
donator
Activity: 2058
Merit: 1007
Poor impulse control.
April 03, 2013, 01:33:17 AM
Perhaps I should have asked instead, how many trials would it take to theoretically reach 1.9% with a 95% confidence interval?

Well alright.  Now I can say "I don't know" instead of "your question sucks" Smiley

It's affected a lot by the big bets.  The profit from thousands of small bets can be wiped out by a single lucky big bet (and vice versa).
The question should have one more number. It should be phrased "95% chance that the house edge will be within 1.89-1.91%" or similarly. The size of the acceptable error there will greatly influence the result.
And... I don't remember how to do a problem like that Cry It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.


I think it can be assessed using Markov chains. Meni Rosenfeld's analysis of PPS pool bankruptcy probabilities (AoBPMRS, Appendix c) examines a similar problem and uses a Markov chain model. I haven't studied them, maybe someone else more familiar with Markov chains could do the analysis.
hero member
Activity: 784
Merit: 1000
0xFB0D8D1534241423
April 03, 2013, 12:16:24 AM
Perhaps I should have asked instead, how many trials would it take to theoretically reach 1.9% with a 95% confidence interval?

Well alright.  Now I can say "I don't know" instead of "your question sucks" Smiley

It's affected a lot by the big bets.  The profit from thousands of small bets can be wiped out by a single lucky big bet (and vice versa).
The question should have one more number. It should be phrased "95% chance that the house edge will be within 1.89-1.91%" or similarly. The size of the acceptable error there will greatly influence the result.
And... I don't remember how to do a problem like that Cry It's complicated by the fact that with 1 trial, there is a 0% chance that the house will take within 1.89 to 1.91 percent.
legendary
Activity: 2940
Merit: 1333
April 02, 2013, 11:35:52 PM
Perhaps I should have asked instead, how many trials would it take to theoretically reach 1.9% with a 95% confidence interval?

Well alright.  Now I can say "I don't know" instead of "your question sucks" Smiley

It's affected a lot by the big bets.  The profit from thousands of small bets can be wiped out by a single lucky big bet (and vice versa).
newbie
Activity: 29
Merit: 0
April 02, 2013, 09:58:34 PM
Over the whole lifetime of the game so far the profit has been around 2.042% before you take transaction fees into account, and 1.952% after deducting transaction fees.

It is mathematically 'supposed' to be 1.9% before subtracting transaction fees, so they're doing better than expected.

I don't remember the details, but the house edge has been adjusted a couple of times.  Not recently, mind you.  I think the most recent adjustment was taking the edge down from 2.0% to 1.9% when a clone site appeared which was offering a lower house edge.  It looked like Erik's way of saying "we can afford to out-compete you so don't even try".  I think before that, the house edge may have been lower than 1.9%, but I really don't remember for sure.

Your question is a little confusing.  The site pays out 1.9% less than true odds.  So in the long run you lose 1.9% of everything you bet.  Every game is effectively random, so you can't say "the profit will be 1.9% over 3 months".  You can't say for certain that the profit will ever go back down to 1.9% from its current level.  All we can say is that the average of the results obtained from a large number of trials should be close to the expected value, and will tend to become closer as more trials are performed.

Perhaps I should have asked instead, how many trials would it take to theoretically reach 1.9% with a 95% confidence interval?
legendary
Activity: 2940
Merit: 1333
April 02, 2013, 09:52:59 PM
Out of curiosity, does anyone know over what period of time the profit is actually 1.9%? Is it 3 months? 9 months? a year? infinity? Obviously we have good months and bad months, but when we are talking about the moving profit average, over what window of time does it actually approach 1.9%?

Over the whole lifetime of the game so far the profit has been around 2.042% before you take transaction fees into account, and 1.952% after deducting transaction fees.

It is mathematically 'supposed' to be 1.9% before subtracting transaction fees, so they're doing better than expected.

I don't remember the details, but the house edge has been adjusted a couple of times.  Not recently, mind you.  I think the most recent adjustment was taking the edge down from 2.0% to 1.9% when a clone site appeared which was offering a lower house edge.  It looked like Erik's way of saying "we can afford to out-compete you so don't even try".  I think before that, the house edge may have been lower than 1.9%, but I really don't remember for sure.

Your question is a little confusing.  The site pays out 1.9% less than true odds.  So in the long run you lose 1.9% of everything you bet.  Every game is effectively random, so you can't say "the profit will be 1.9% over 3 months".  You can't say for certain that the profit will ever go back down to 1.9% from its current level.  All we can say is that the average of the results obtained from a large number of trials should be close to the expected value, and will tend to become closer as more trials are performed.
newbie
Activity: 29
Merit: 0
April 02, 2013, 09:43:17 PM

It seems to be doing so.

750 BTC profit after 2 days.  That clearly means we'll be up 11,250 BTC by the end of the month.  Smiley
Any chance of a confidence interval for that figure? Wink

lol

Out of curiosity, does anyone know over what period of time the profit is actually 1.9%? Is it 3 months? 9 months? a year? infinity? Obviously we have good months and bad months, but when we are talking about the moving profit average, over what window of time does it actually approach 1.9%?
donator
Activity: 2058
Merit: 1007
Poor impulse control.
April 02, 2013, 09:37:23 PM
Wow, if that luck keeps up for the rest of the month

It seems to be doing so.

750 BTC profit after 2 days.  That clearly means we'll be up 11,250 BTC by the end of the month.  Smiley

Any chance of a confidence interval for that figure? Wink
legendary
Activity: 2940
Merit: 1333
April 02, 2013, 08:58:17 PM
Wow, if that luck keeps up for the rest of the month

It seems to be doing so.

750 BTC profit after 2 days.  That clearly means we'll be up 11,250 BTC by the end of the month.  Smiley
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