bobgio
Joined: Sep 19, 2013
• Posts: 2
October 2nd, 2013 at 10:07:04 PM permalink
I've noticed on an electronic craps machine (where the dice are "rolled" by bouncing them on a drum that is vibrated) that whenever I look at the statistics showing the number of times a 7 is rolled in the last 100 rolls, I have noticed that it's more often than not 23 thru 27 times out of the last 100 rolls than 7 through 10 times. The average should be 16 or 17 (since the average # of times a 7 is rolled is should be statistically 16.67%).

Since 23 thru 27 times is 7 to 10 times above the expected average, I would expect the board to show an equal amount of occurences of a 7 thru 10 times the 7 has hit in the last 100 rolls (i.e. the same number below the average as I've seen above the average. But I've never seen it that low. The lowest I've seen it is 15 times of the last 100 rolls).

My question is: Is this an acceptable rate for the 7 to be showing (i.e. if different from the norm of 16.67% then it is more likely higher rather than lower)? Or is the fact that the 7 is the most common outcome make it more likely to be higher than the norm than below the norm?

Or, since most bettors are place or pass line bettors, could the machine be purposely skewed (i.e. cheating the players).

Can someone with a statistics background let me know if what I observe (more than likely chance of the % of 7's hitting is above the norm than below the norm or 16.67%) is unusual or acceptable?

I've seen this over a 9 month period at random times in 2 different casinos (Empire City in Yonkers NY and Resort World in Queens NY)

Thanks,
Bob
7craps
Joined: Jan 23, 2010
• Posts: 1883
October 2nd, 2013 at 10:52:19 PM permalink
Quote: bobgio

My question is:
Is this an acceptable rate for the 7 to be showing
(i.e. if different from the norm of 16.67% then it is more likely higher rather than lower)?
Or is the fact that the 7 is the most common outcome make
it more likely to be higher than the norm than below the norm?

looks fine to me

at the 2SD point.

Quote: bobgio

Or, since most bettors are place or pass line bettors,
could the machine be purposely skewed (i.e. cheating the players).

anything is possible,
but I say not probable
due to any type of honest cheating.

The binomial probability distribution is positively skewed at 0.1789
the data
out of the 101 possible outcomes for the # of 7s in 100 rolls,
23 looks to be the 13th highest.
` x    prob[X=x]   prob[X<x]  prob[X>=x]  prob[X<=x]   prob[X>x] 5   0.00029090  0.00009402  0.99990598  0.00038492  0.99961508 6   0.00092119  0.00038492  0.99961508  0.00130612  0.99869388 7   0.00247406  0.00130612  0.99869388  0.00378018  0.99621982 8   0.00575219  0.00378018  0.99621982  0.00953237  0.99046763 9   0.01176004  0.00953237  0.99046763  0.02129241  0.9787075910   0.02140327  0.02129241  0.97870759  0.04269568  0.9573043211   0.03502354  0.04269568  0.95730432  0.07771922  0.9222807812   0.05195158  0.07771922  0.92228078  0.12967080  0.8703292013   0.07033445  0.12967080  0.87032920  0.20000525  0.7999947514   0.08741567  0.20000525  0.79999475  0.28742092  0.7125790815   0.10023663  0.28742092  0.71257908  0.38765755  0.6123424516   0.10650142  0.38765755  0.61234245  0.49415898  0.5058410217   0.10524847  0.49415898  0.50584102  0.59940744  0.4005925618   0.09706247  0.59940744  0.40059256  0.69646992  0.3035300819   0.08378024  0.69646992  0.30353008  0.78025016  0.2197498420   0.06786200  0.78025016  0.21974984  0.84811215  0.1518878521   0.05170438  0.84811215  0.15188785  0.89981653  0.1001834722   0.03713314  0.89981653  0.10018347  0.93694967  0.0630503323   0.02518596  0.93694967  0.06305033  0.96213563  0.0378643724   0.01616099  0.96213563  0.03786437  0.97829662  0.0217033825   0.00982588  0.97829662  0.02170338  0.98812250  0.0118775026   0.00566878  0.98812250  0.01187750  0.99379128  0.0062087227   0.00310733  0.99379128  0.00620872  0.99689861  0.0031013928   0.00162025  0.99689861  0.00310139  0.99851886  0.0014811429   0.00080454  0.99851886  0.00148114  0.99932340  0.0006766030   0.00038081  0.99932340  0.00067660  0.99970422  0.00029578`
the chance of 23 or more is (4th column)
0.06305033 or about 1 in 16

the chance of 10 or less is (5th column)
0.04269568 or about 1 in 24

of course the machine is showing you a window to the last 100 rolls.
that window moves each roll so you may see
a certain # of 7s stay there for some time until they finally drop out of the last 100 rolls.

Thanks for sharing your observation and questions
hope this helps
winsome johnny (not Win some johnny)
tringlomane
Joined: Aug 25, 2012
• Posts: 5988
October 2nd, 2013 at 10:54:00 PM permalink
Quote: bobgio

My question is: Is this an acceptable rate for the 7 to be showing (i.e. if different from the norm of 16.67% then it is more likely higher rather than lower)? Or is the fact that the 7 is the most common outcome make it more likely to be higher than the norm than below the norm?

Or, since most bettors are place or pass line bettors, could the machine be purposely skewed (i.e. cheating the players).

Can someone with a statistics background let me know if what I observe (more than likely chance of the % of 7's hitting is above the norm than below the norm or 16.67%) is unusual or acceptable?

I've seen this over a 9 month period at random times in 2 different casinos (Empire City in Yonkers NY and Resort World in Queens NY)

Thanks,
Bob

How acceptable it is really depends on the number of observations you have taken.

It could be rigged, but I doubt it, especially if it's a unit used in casinos in other states like Nevada.
paisiello
Joined: Oct 30, 2011
• Posts: 546
October 2nd, 2013 at 10:54:47 PM permalink
Quote: bobgio

...The lowest I've seen it is 15 times of the last 100 rolls).

How many sets of 100 rolls did you actually observe?

Quote: bobgio

My question is: Is this an acceptable rate for the 7 to be showing (i.e. if different from the norm of 16.67% then it is more likely higher rather than lower)? Or is the fact that the 7 is the most common outcome make it more likely to be higher than the norm than below the norm?

Again it would depend on how many 100 roll observations you made. And it doesn't matter whether the observations were higher or lower than the norm. You would actually never see exactly the norm. You would always expect to see higher or lower results than the norm.
odiousgambit
Joined: Nov 9, 2009
• Posts: 8112
October 5th, 2013 at 4:02:27 AM permalink
The stats are always for the last 100 rolls, so you are never seeing good data .... good data would be for the last 100,000 rolls or preferably more. Even 10,000 might show a skew. What you are seeing, even if you are there a lot, is similar to just anecdotal.

But if you are convinced, go to the Darkside, sir.
the next time Dame Fortune toys with your heart, your soul and your wallet, raise your glass and praise her thus: “Thanks for nothing, you cold-hearted, evil, damnable, nefarious, low-life, malicious monster from Hell!” She is, after all, stone deaf. ... Arnold Snyder
Tanko
Joined: Apr 22, 2013
• Posts: 972
October 5th, 2013 at 6:46:23 AM permalink
Quote: bobgio

I've noticed on an electronic craps machine (where the dice are "rolled" by bouncing them on a drum that is vibrated) that whenever I look at the statistics showing the number of times a 7 is rolled in the last 100 rolls, I have noticed that it's more often than not 23 thru 27 times out of the last 100 rolls than 7 through 10 times. The average should be 16 or 17 (since the average # of times a 7 is rolled is should be statistically 16.67%).

I've played those Interblock machines at RW and Empire a number of times. They are not skewed by the Casino. Over time, all the numbers will roll normally, but one or two numbers or sequences seem to get hot before turning very cold. Consequently, the tote board might show the eight rolled fourteen times in 100 rolls, but it does not show that seven of those fourteen hits occurred within a fifteen roll span.

Could the Bubble be too small to adequately shake the three dice (one for Sic-Bo) it contains?

On many occasions I saw one crowded die simply vibrating in place or flopping from side to side between the same two numbers.

I've seen the Seven roll seven times consecutively on two occasions. I've also seen all three dice roll the same 5,2,3 twice in a row, and the Six and Eight roll back to back five times in a row.

I've also seen and the Seven roll only three times in 100 rolls while the Twelve rolled eight times and the Two rolled five times in the same 100 roll period.

All of these events are statistically possible, but I question whether these results were truly random or due to the dice not being adequately shaken in the bubble.

A few Regulars at RW make nothing but Place, Buy, Hardway, Yo and Craps bets based solely upon the tote board results.

One regular sitting next to me once said "Why aren't you Placing the Nine? Look at the board. It's like reading a book. They're telling you what to bet."

As for me, I stay away from those Robots and prefer to "shake-em" at the real tables.
odiousgambit
Joined: Nov 9, 2009
• Posts: 8112
October 7th, 2013 at 2:54:36 AM permalink
Quote: Tanko

One regular sitting next to me once said "Why aren't you Placing the Nine? Look at the board. It's like reading a book. They're telling you what to bet."

Gee, for some reason having "them" tell you what to bet doesnt seem to work out. Well, of course, I can't really confirm that the old veteran wasn't getting rich by thinking the past predicted the future in craps, but it does fit perfectly into the category of "gambler's fallacy".

If you can truly see that you will have "one crowded die simply vibrating in place" then maybe you have something. Since you'd rather be at a real table, you'll forgive me for thinking it would not seem you could place your bet in time to take advantage of it.
the next time Dame Fortune toys with your heart, your soul and your wallet, raise your glass and praise her thus: “Thanks for nothing, you cold-hearted, evil, damnable, nefarious, low-life, malicious monster from Hell!” She is, after all, stone deaf. ... Arnold Snyder
s2dbaker
Joined: Jun 10, 2010
• Posts: 3259
October 7th, 2013 at 3:15:16 AM permalink
If a machine were programmed to skew the results in favor of the casino, then the manufacturer of that machine would do everything in their power to hide result histories.
Someday, joor goin' to see the name of Googie Gomez in lights and joor goin' to say to joorself, "Was that her?" and then joor goin' to answer to joorself, "That was her!" But you know somethin' mister? I was always her yuss nobody knows it! - Googie Gomez
Tanko
Joined: Apr 22, 2013
• Posts: 972
October 7th, 2013 at 9:29:40 AM permalink
deleted
Last edited by: Tanko on Mar 10, 2016
7craps
Joined: Jan 23, 2010
• Posts: 1883
October 7th, 2013 at 10:28:49 AM permalink
Quote: Tanko

I recorded these rolls during my last visit:

8,3,4,11,3,8,10,10,3,6,5,6,6,7,6,9,2,5,6,5,7,7,5,9,7,6,10,7,7,11,3,8,11,9,9,8,9,4,6,8,6,8,8,12,11,10,8,6,3,6,9,7,7,8,10,10,8,7,8,8,9,9,8,
5,7,8,5,10,11,10,7,2,6,6,9,8,10,8,4,8,9,4,7,9,8,3,9,10,9,10,6,9,5,6,7,5,7,8,10,6,11,8,2,8,3,11,5,9,12,8,8,8,8,6,7

I hope you at least
played the pass with some kind of odds. I think you did.

A right way player should have easily
made good \$\$\$ on these 9 hands.

Just \$5 pass and 2X odds shows \$197 net profit (\$212 was max high)
345X odds shows \$365 net profit (\$395 was the max high)
never more than \$5 plus odds into the starting bankroll

I also noticed on this type of machine, only one in SoCal,
the pass point, when it wins, does it very quickly.
(hands 3,4 and 6 had no point winners)

the first # 8 as first come out roll
shooter (Hand) #1
cor 8,3,4,11,3,8,win (6,#)
cor 10,10,win (2,#)
cor 3,crap out (1,#)
cor 6,5,6,win (3,#)
cor 6,7,out (2,#)
shooter (Hand) #1 14 roll hand
5 # COR
3 # Point Wins
3 # Fire Bets
3,2 shooter (Hand) score: pass,miss
2 # Place Hits

shooter (Hand) #2
cor 6,9,2,5,6,win (5,#)
cor 5,7,out (2,#)
shooter (Hand) #2 7 roll hand
2 # COR
1 # Point Wins
1 # Fire Bets
1,1 shooter (Hand) score: pass,miss
2 # Place Hits

shooter (Hand) #3
cor 7,win (1,#)
cor 5,9,7,out (3,#)
shooter (Hand) #3 4 roll hand
2 # COR
0 # Point Wins
0 # Fire Bets
1,1 shooter (Hand) score: pass,miss
1 # Place Hits

shooter (Hand) #4
cor 6,10,7,out (3,#)
shooter (Hand) #4 3 roll hand
1 # COR
0 # Point Wins
0 # Fire Bets
0,1 shooter (Hand) score: pass,miss
1 # Place Hits

shooter (Hand) #5
cor 7,win (1,#)
cor 11,win (1,#)
cor 3,crap out (1,#)
cor 8,11,9,9,8,win (5,#)
cor 9,4,6,8,6,8,8,12,11,10,8,6,3,6,9,win (15,#)
cor 7,win (1,#)
cor 7,win (1,#)
cor 8,10,10,8,win (4,#)
cor 7,win (1,#)
cor 8,8,win (2,#)
cor 9,9,win (2,#)
cor 8,5,7,out (3,#)
shooter (Hand) #5 37 roll hand
12 # COR
5 # Point Wins
2 # Fire Bets
10,2 shooter (Hand) score: pass,miss
15 # Place Hits

shooter (Hand) #6
cor 8,5,10,11,10,7,out (6,#)
shooter (Hand) #6 6 roll hand
1 # COR
0 # Point Wins
0 # Fire Bets
0,1 shooter (Hand) score: pass,miss
3 # Place Hits

shooter (Hand) #7
cor 2,crap out (1,#)
cor 6,6,win (2,#)
cor 9,8,10,8,4,8,9,win (7,#)
cor 4,7,out (2,#)
shooter (Hand) #7 12 roll hand
4 # COR
2 # Point Wins
2 # Fire Bets
2,2 shooter (Hand) score: pass,miss
5 # Place Hits

shooter (Hand) #8
cor 9,8,3,9,win (4,#)
cor 10,9,10,win (3,#)
cor 6,9,5,6,win (4,#)
cor 7,win (1,#)
cor 5,7,out (2,#)
shooter (Hand) #8 14 roll hand
5 # COR
3 # Point Wins
3 # Fire Bets
4,1 shooter (Hand) score: pass,miss
4 # Place Hits

shooter (Hand) #9
cor 8,10,6,11,8,win (5,#)
cor 2,crap out (1,#)
cor 8,3,11,5,9,12,8,win (7,#)
cor 8,8,win (2,#)
cor 8,6,7,out (3,#)
shooter (Hand) #9 18 roll hand
5 # COR
3 # Point Wins
1 # Fire Bets
3,2 shooter (Hand) score: pass,miss
5 # Place Hits

shooter (Hand) #10
cor
waiting...
thanks for sharing
winsome johnny (not Win some johnny)