I just had three public level 3 giveaways end at the same time. Each had a little over 400 entries. One user won two of them!

Any mathematicians around to check my math here? Thanks!

Out of 2 giveaways with 400 contestants each, let's assume all 400 entrants are the same in both giveaways.

How many ways are there for different entrants to win the 2 giveaways? 399 + 398 +397... = x
How many ways are there for the same entrant to win both giveaways? 400
What are the chances that one entrant will win both giveaways? 400/x

5 years ago*

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5 years ago
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Happens. ^^

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it wasn't that anonymous guy again was it? he wins everything
not my joke but worth retelling

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Inb4 someone blames it on bots.

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It is not uncommon. The picking is not fully random but i don't have figured out the algorithm behind it maybe in the future....

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Huh? it isn't random?

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Yes, it's as random as a computer RNG gets.
It's not 100% accurate, but close enough that the difference is negligible.

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uh.

care to elaborate a LOT more, bro? :D

meaning: i literally crave for these things... thought that was 100% randomness.

(and always <3'd randomness)

5 years ago
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With as small a sample as we're getting on Steamgifts, you wouldn't be able to tell the difference between true random numbers and those generated by an algorithm. For all intents and purposes the numbers generated on Steamgifts are "random."

https://www.howtogeek.com/183051/htg-explains-how-computers-generate-random-numbers/

5 years ago*
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i'll read that, obviously. but i thought there were something "SG specific" (a bug or smth).

so, "Yes, it's as random as a computer RNG gets" is 100% accurate :D

grazie Tz!

edit: that :P

5 years ago
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The TLDR version: Yes, they're random, but like with any random set of possibilities, you'll occasionally get "freak occurrences" that don't appear random -- but that's just our perception telling us that because of the odds we expect.

For instance, it's entirely possible for you to roll a 6-sided die and come up with ones 100 times in a row. The odds are so much against it, though, that you might then be led to believe the die is weighted.

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was asking you just that.

do you, Tzaar, feel SG numbers as random? cause i definitely do.

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Computer RNG works more or less this way (afaik):

  • there is a "seed number", that is set when a program compiles (bad), the program starts (a little less bad) or initiated before your random picking (kind of good). The number is calculated from several parameters of the computer's hardware (and software), e.g. date.
  • the seed is fed to an algorithm to produce a random number. If there are two processes that start at the excat same time, using the same algorithm and seed, both processes should yield the same "random number", thus the same winner, assuming the generated random number is associated with the SG user name or the winner is at the same position in the list of entries in both giveaways.

Writing the text, I think of other obstacles to explain it so simple.
Anyways, hope above helps you slightly along.

5 years ago
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Ah, I knew you'd be along sooner or later to better explain things. :3

5 years ago
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+100%

...wait

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Oppen ti amo

it helps a lot, and it kinda makes SG "odds" even more fascinating.

Seed number is very often calculated on date/current time, right? Like Steam Guard or various authenticators, bank accounts "tokens" etc... ?
then you send it to the algorithm to produce a random number, and, in our site, pick the winner.

...oh, wow, the more i think about this the more it becomes interesting. and kinda harder :P

thanks a ton

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not exactly, the "seed" basically determines the initial state of the RNG, then each call to the RNG modifies the maintained state and produces a new random number.

Hence if you reset the process and fill in the same seed used in a previous run, you should get the same sequence of numbers. Think of it as many many seemingly random but fixed paths, it all depends on where you start.

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Think of it as many many seemingly random but fixed paths, it all depends on where you start.

very, very nice image

5 years ago
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illusion

<3

oh my, what a saturday morning i'm having. thank you, guys.

so if you're having a problem with a cheap game, try playing it at a different time of day

huge!

milliseconds matter

ah ha. that was a thing i'm kinda suspecting since long time... ESGST has options to display the time in a 24 hours format, or with seconds... so i thought, "why seconds?" (using that option since then...)

now, with gibs ending at the exact same time. is that even possible?
i've created a lot of those, cause is cool to have multiple spacecats showing up at the same time, you feel like.. even more lucky. but is possible to have two same ....

SG uses live scripts (not compiled) so a fresh seed is inserted for every gib

ok, nevermind, then :P

grrrrazie, veebles

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he should start play lottery :)

5 years ago
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Had the same once :) Although I was the winner :) Guess it's not that uncommon.

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Probably an immigrant stealing our jobs and giveaways

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It might not be as amazing as it looks! :)

Let's suppose you had only 2 giveaways instead of 3 and both had exactly 400 entries (to simplify the math). It looks like the probability is about 1 / 160000 (1/400 squared). And if we asked in advance what is the probability for this particular user to win these two GAs, the answer would indeed be 1 / 160000. But if we ask what is the probability that any user wins both GAs (in a simplified problem where all the same 400 users entered both giveaways), we should multiply the result by the number of users and get 1/400.

Or, in other words, the probability that any user wins one giveaway is 1. The probability that this same user wins the second giveaway is thus 1/400.

It's related to the well-known but still a bit mind-blowing Birthday problem, where it turns out that in a room of just 23 people there’s a 50% probability of two people having the same birthday.

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Very well put, and explained. And yes, the Birthday problem is totally mind blowing when you just quickly think about it, but kind of makes sense when you explain it. Probability is weird...

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Out of 2 giveaways with 400 contestants each, let's assume all 400 entrants are the same in both giveaways.

How many ways are there for different entrants to win the 2 giveaways? 399 + 398 +397... = x
How many ways are there for the same entrant to win both giveaways? 400
What are the chances that one entrant will win both giveaways? 400/x

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1/400 that one guy wins both

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That's an amazing portion of luck, no doubt about it.
Some other users already cared to explain how the RNG works, and even if it's not possible to generate 100% true randomness, it's not a thing you can actually exploit.
Luck is a very fascinating and dangerous subject, gambling can literally break your neck if you lack luck, but one thing I cannot explain is how some people have significantly more luck than others. I'm curious if the winner of your gibs is one of those luckers. ;)

5 years ago*
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To win two out of two, it's 1 in 160,000.
1 / 400^2
For two out of three, it's 1 in 53,467.
Each trial has 1/400 chance of success = 0.0025
2 trials successful out of 3.
P(2,3,0.0025) = {3! / [2! (3-2)!]} (0.0025)^2 (1 - 0.0025)^(3-2)
P(2,3,0.0025) = {6 / [2
1]} (0.0025)^2 (0.9975)
P(2,3,0.0025) = 3 (0.0025)^2 (0.9975)
P(2,3,0.0025) = 0.00001870, which is 1/ 53,467
(3*399 / 400^3)

5 years ago
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Thank you so much! My statistics is rusty.

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