Unlucky Tickets?!

Discussion in 'Tickets' started by Ubik, Mar 17, 2016.

  1. 2017/12/15 - Decred v1.1.2 released! → Release Notes  → Downloads
  1. Ubik

    Ubik New Member
    Translator (Italiano)

    Feb 12, 2016
    49
    13
    I've bought almost 40 tickets (in the PoS pool), thinking that if it's true that 50% of them get to vote in the first 28 days, i should be able to vote a bit less than 2 times in 3 days. Or atleast once every two days, if i'm a bit unlucky...

    Now a week has passed and i'm still waiting for my first vote.. did i buy some kind of cursed tickets?



    Assuming that there are 256 blocks per day and every block allows for 4.8 votes average, there are more than 1228 extracted tickets per day. 8600 per week. And yet not one of my tickets was the lucky one.

    Is my math correct? Am i really this unlucky or is there something i don't get? Should i search for some ancient fortune-bringing rituals?!
     
  2. Kandiru

    Kandiru Member

    Feb 21, 2016
    206
    87
    The odds do seem to be under 0.1% that you wouldn't have any votes in 6 days (1day they are immature) of blocks. Is your wallet running and unlocked the entire time? What do you get if you run dcrct --wallet getstakeinfo?
     
  3. Shadowlance

    Shadowlance Full Member

    Jan 9, 2016
    220
    155
    Male
    #3 Shadowlance, Mar 17, 2016
    Last edited: Mar 17, 2016
    > P <-40/41555
    > N <- 288*6
    > 1 - (1 - P)^N
    [1] 0.8106463

    So there's an 81% chance you'll get a vote in 6 days. Which means there's a 19% chance you won't. Unlucky, yes, but not hugely so.

    You've picked the unlucky 1 in 5.
     
    ClokworkGremlin likes this.
  4. ClokworkGremlin

    ClokworkGremlin Sr. Member

    Jan 10, 2016
    535
    381
    Male
    Whatever I want.
    Probability doesn't really work like that. And at the same time, probability kind of works exactly like that. Probability is funny.

    The current size of the stake pool is 41565. That means if you bought 40 tickets, your representation in the stake pool is ~1/1000. It's not quite exactly like that, but the exact calculations are tedious, and this approximation is close enough.

    Now, 1440 tickets (24 hours * 60 minutes / 5 minutes * 5 tickets) are selected to vote per day, and on average you should expect 1 ticket to vote per 200 blocks, so if you bought 40 tickets, it's not at all unreasonable to expect about 2 votes every 3 days. (your odds will fall off as your tickets are pulled out of the pool, but again, the actual math is tedious.)

    So in the past week, about 8400 tickets have been selected to vote. Now, that's 1/5 of the total stake pool, which means that any 1 ticket only has a 1/5 chance to have been selected, but you bought 40 tickets, so you would expect to have voted 8 times in that period. Because probability absolutely does work that way.

    But at the same time, when a vote comes up, the odds of any one ticket being selected are still only 1/8313, even if that ticket has already been in the stake pool for 36000 blocks. Because probability also works that way.

    To put it a little more succinctly, because each face on a six-sided die has (approximately) a 1/6 chance of appearing, probability says that to have each face come up once, you should roll the die 6 times, but in practice, you would actually be amazed to see the die come up with a different face for 6 rolls in a row, because the odds of that happening are actually (if I haven't messed anything up) closer to 1.5%. It's more likely to have each face show up twice in 12 attempts, and if you're rolling the die 6000 times, it's pretty certain that each face will show up between 990 and 1010 times.

    There are no cursed tickets, just some that will take longer than others to vote. If you want your tickets to behave in a more cleanly probabilistic manner, buy more to even out the odds.
     
    Noah, CrzyTed and Shadowlance like this.
  5. Kandiru

    Kandiru Member

    Feb 21, 2016
    206
    87
    It's 5 votes per block, not 1! :) I may have made a mistake though.
     
  6. Ubik

    Ubik New Member
    Translator (Italiano)

    Feb 12, 2016
    49
    13
    #6 Ubik, Mar 17, 2016
    Last edited: Mar 17, 2016
    I think you are right! It should be:
    > P <-40/41555
    > N <- 1440*6
    > 1 - (1 - P)^N
    Soo (if i'm not mistaken) like a 1/1000 chance to NOT get extracted even once?
    Wow!


    @ClokworkGremlin yep, i know that even very unlikely events do happen eventually (it's part of the beauty of our universe) , i just wanted to know how unlikely it was and therefore how unlucky i was :p
     
  7. davecgh

    davecgh Hero Member
    Developer Organizer

    Dec 31, 2015
    642
    788
    Male
    United States
    While I totally agree with your overall post, I did want to point out that this part is not really true. The problem here is you're assuming that the tickets that are already in the pool have an advantage because they're already there. However, that's not how it works. In order to see why, let's scale the numbers way down, but keep the proportions.

    Assume the pool only has 50 tickets and 10 of them are yours. That also gives you 1/5 of the total pool. Let's number these first 50 tickets as 0-49 and say that tickets 0-9 are yours for illustrative purposes.

    Now, a block comes in and 5 votes are cast, but up to 20 new tickets become mature and are added to the pool. To simplify, let's just assume only 5 tickets are added per block here to maintain equilibrium. So, let's say that votes 13, 18, 27, 38, and 45 are selected and vote and hence removed from the pool. The new tickets 50-54 are added to the pool. Another block comes in and let's say this time 16, 21, 23, 51, and 53 (yes two of the votes that were just added) are selected. New tickets 55-59 are added to the pool.

    At this point, there would have been 10 votes, exactly 1/5 of the pool, but it absolutely did not turn over 1/5 of the tickets in the pool at the time of the original ticket purchases in question because 2 of those tickets were not part of the existing tickets at that moment in time.
     
    ClokworkGremlin likes this.
  8. ClokworkGremlin

    ClokworkGremlin Sr. Member

    Jan 10, 2016
    535
    381
    Male
    Whatever I want.
    My post was intended to be a rather gross oversimplification of the topic, focusing more on qualitative analysis than quantitative, but thanks for illustrating that more in-depth.

    Probability is fun. Tedious, but lots of fun.
     
    davecgh likes this.
  9. Shadowlance

    Shadowlance Full Member

    Jan 9, 2016
    220
    155
    Male
    Whoops, yes, that's right. I forgot about the 5. So yes, it's a 0.1% chance of not voting.

    Don't go outside...

    Seriously, though. To make sure everything is ok, check your wallet and make sure you're seeing lines like "Connecting block...". If you're seeing that then the wallet is connected and working. You can also try 'dcrctl --wallet getstakeinfo' and check missed tickets. It's possible some were selected by didn't vote. If this is the case you'll find an entry in the wallet log (~/dcrd/dcrwallet I think).
     
  10. Noah

    Noah Member
    Advocate (Twitter)

    Feb 1, 2016
    154
    97
    Male
    Amsterdam
    In order to avoid downtime, just use the PoS pool: https://stakepool.decred.org/
     
  11. Ubik

    Ubik New Member
    Translator (Italiano)

    Feb 12, 2016
    49
    13
    Yep, i specified in the OP that i was using the PoS pool.
    Anyways, one of you guys did bring me fortune, since the opening of the tread i voted twice!
     
  12. RandaFlores

    RandaFlores New Member

    Apr 23, 2019
    39
    0
    Female
    London
    Beauty is everywhere and it really helps to work and to live. Girls can make their appearance great and marvelous with the help of reliable cosmetics like https://www.alyaka.com/brands/ and enjoy the result of it. Why not if there are so many quality goods that can make the skin younger and respected.
     

Share This Page