Hello folks,
I am beginning to have some doubt about the actual randomness of train generation from portals. I noticed some portal-generated trains appear much often than others that are very rarely seen, so I took some notes while testing a session.
The session uses 4 portals (actually, trackmarks configured as portals using the "Un-portal" rule) to generate random freight trains. Portal 1 has a 6-consist list, Portal 2 has a 7-consist list, Portals 3 & 4 have a 4-consist list.
NOTE: A friend of mine has noticed the same behaviour - even though he has not recorded it - when using the "Un-portal 2" rule. We do not know it this issue also applies to other portal types (e.g. the standard Auran built-in portals), but we think - maybe wrongly - the random selection process used is the same.
These are the data I collected after 40 tests:
As you can see, in all portals Train #1 is generated much often than expected: 180% to 225%; the same could also be true - to a lesser extent - for the last train (100% to 140%).
Is this effect inevitable - and associated with the way computers generate random variables - or there are ways to obtain uniformly distributed random results?
Thanks in advance.
I am beginning to have some doubt about the actual randomness of train generation from portals. I noticed some portal-generated trains appear much often than others that are very rarely seen, so I took some notes while testing a session.
The session uses 4 portals (actually, trackmarks configured as portals using the "Un-portal" rule) to generate random freight trains. Portal 1 has a 6-consist list, Portal 2 has a 7-consist list, Portals 3 & 4 have a 4-consist list.
NOTE: A friend of mine has noticed the same behaviour - even though he has not recorded it - when using the "Un-portal 2" rule. We do not know it this issue also applies to other portal types (e.g. the standard Auran built-in portals), but we think - maybe wrongly - the random selection process used is the same.
These are the data I collected after 40 tests:
Portal #1 | Generated | Actual % | Expected % | Actual/Expected |
Train #1 | 15 | 37,5% | 16,7% | 225% |
Train #2 | 3 | 7,5% | 16,7% | 45% |
Train #3 | 5 | 12,5% | 16,7% | 75% |
Train #4 | 4 | 10,0% | 16,7% | 60% |
Train #5 | 4 | 10,0% | 16,7% | 60% |
Train #6 | 9 | 22,5% | 16,7% | 135% |
40 | ||||
Portal #2 | ||||
Train #1 | 11 | 28% | 14,3% | 193% |
Train #2 | 3 | 8% | 14,3% | 53% |
Train #3 | 5 | 13% | 14,3% | 88% |
Train #4 | 2 | 5% | 14,3% | 35% |
Train #5 | 6 | 15% | 14,3% | 105% |
Train #6 | 5 | 13% | 14,3% | 88% |
Train #7 | 8 | 20% | 14,3% | 140% |
40 | ||||
Portal #3 | ||||
Train #1 | 18 | 45% | 25,0% | 180% |
Train #2 | 5 | 13% | 25,0% | 50% |
Train #3 | 6 | 15% | 25,0% | 60% |
Train #4 | 11 | 28% | 25,0% | 110% |
40 | ||||
Portal #4 | ||||
Train #1 | 19 | 48% | 25,0% | 190% |
Train #2 | 4 | 10% | 25,0% | 40% |
Train #3 | 7 | 18% | 25,0% | 70% |
Train #4 | 10 | 25% | 25,0% | 100% |
40 |
As you can see, in all portals Train #1 is generated much often than expected: 180% to 225%; the same could also be true - to a lesser extent - for the last train (100% to 140%).
Is this effect inevitable - and associated with the way computers generate random variables - or there are ways to obtain uniformly distributed random results?
Thanks in advance.