The Binding of Isaac: Rebirth

The Binding of Isaac: Rebirth

JPlanas98 Dec 4, 2021 @ 8:45am
Eternal D6 percentage doesn't seem right
Eternal D6 is supposed to have a 30% chance of the item disappearing. I've used Eternal D6 a total of 18 times (I've counted) and it's only re-rolled the items 3 of those times. Now, I'm not the best at math, but that seems like a lot higher than 30%
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Showing 1-15 of 23 comments
Sentient Entropy Dec 4, 2021 @ 8:49am 
Humans are terrible at perceiving randomness.
blietborne Dec 4, 2021 @ 8:55am 
Just unlucky lol, say hello to Edmund
blietborne Dec 4, 2021 @ 8:56am 
Its like having a run with a few decent items and then all pills are stat down for some reason
squat_instructor Dec 4, 2021 @ 9:04am 
what you described is pseudo-random engine, which is used games sometimes, but not in this one
JPlanas98 Dec 4, 2021 @ 9:25am 
I now have had 4/23 items re-roll.
Nazemec Dec 4, 2021 @ 9:30am 
Originally posted by Sentient Entropy:
Humans are terrible at perceiving randomness.
Indeed. There are a lot of cognitive biases involved.
One is to believe that, for example, getting heads from a coin toss five times in a row gives a higher chance to get tails on the next one. Truth is: it does not. The coin doesn't care about previous tosses. (This one is called "Gambler's Fallacy").
This thread is apparently an example of this bias. :dip:

OP, do your math once you are at a few thousands attempts. A few dozens isn't enough to use statistics reliably.
JPlanas98 Dec 4, 2021 @ 2:39pm 
Originally posted by Nazemec:
Originally posted by Sentient Entropy:
Humans are terrible at perceiving randomness.
Indeed. There are a lot of cognitive biases involved.
One is to believe that, for example, getting heads from a coin toss five times in a row gives a higher chance to get tails on the next one. Truth is: it does not. The coin doesn't care about previous tosses. (This one is called "Gambler's Fallacy").
This thread is apparently an example of this bias. :dip:

OP, do your math once you are at a few thousands attempts. A few dozens isn't enough to use statistics reliably.
You expect me to use eternal D6 a few thousand times? That's completely stupid. At most 100 tries is enough to determine.
Tato Dec 4, 2021 @ 3:31pm 
Originally posted by JPlanas98:
Originally posted by Nazemec:
Indeed. There are a lot of cognitive biases involved.
One is to believe that, for example, getting heads from a coin toss five times in a row gives a higher chance to get tails on the next one. Truth is: it does not. The coin doesn't care about previous tosses. (This one is called "Gambler's Fallacy").
This thread is apparently an example of this bias. :dip:

OP, do your math once you are at a few thousands attempts. A few dozens isn't enough to use statistics reliably.
You expect me to use eternal D6 a few thousand times? That's completely stupid. At most 100 tries is enough to determine.
Well, uncertainty decreases with the reciprocal of sqrt(N), so you'll want as large a sample size as possible. I'm not sure that 100 would be statistically significant.
Nazemec Dec 4, 2021 @ 4:47pm 
Originally posted by JPlanas98:
You expect me to use eternal D6 a few thousand times? That's completely stupid. At most 100 tries is enough to determine.
No. I expect you to stop trying to use statistics on such a little number of tries as it has a very low chance to mean anything. :dip:
HeyThere Dec 4, 2021 @ 4:48pm 
I'm pretty sure that if you used it 18 times, and there is a 30% chance of the items disappearing, and the items disappeared 15 times, then there should be a 0.0004% chance of that happening, which is definitely curious.

However, that number could be wrong, but also, as others have stated, a sample size of 18 is very small. 100 would be better, maybe 250 would suffice (I'm not saying literally use the eternal dice 250 times; maybe find a way to make a simulation?)
Danizk0 Dec 4, 2021 @ 6:24pm 
While we're on the topic of randomness, let's talk about fortune telling machines. Has anyone else noticed that their payout chance is significantly lower than what it used to be in Ab+? I did a test back in April, where after depositing 400 coins, I only won 61 times (15.25%) despite the fact that those machines are supposed to have a 35% payout chance. The patchnotes never said anything about it being reduced and those machines are allegedly unaffected by the hard mode chance decrease that affects regular slot machines.
Last edited by Danizk0; Dec 4, 2021 @ 6:32pm
UwU Dec 4, 2021 @ 6:32pm 
Originally posted by Danizk0:
While we're on the topic of randomness, let's talk about fortune telling machines. Has anyone else noticed that their payout chance is significantly lower than what it used to be in Ab+? I did a test back in April, where after depositing 400 coins, I only won 61 times (15.25%) despite the fact that those machines are supposed to have a 35% payout chance. The patchnotes never said anything about it being reduced and those machines are supposedly unaffected by the hard mode chance decrease that affects regular slot machines.
Def feels lower, but at the same time can't really tell if it's just a luck thing. I get the same feeling every time when I play crane machine, getting nothing out of it after spending ~50 coins. A bit too much for 1/4 chance. Sometimes I'm wondering if there's some hidden "screw you" mechanic in the game for luck based things
Danizk0 Dec 4, 2021 @ 6:47pm 
Originally posted by UwU:
Sometimes I'm wondering if there's some hidden "screw you" mechanic in the game for luck based things
That was actually a popular playground rumor in the Flash Isaac community! I remember people telling each other to always keep at least 1 key and 1 bomb on themselves because otherwise the troll engine would start giving you more things to spend your keys/bombs on while not actually giving you the required resource. Sadly, the theory died out when seeds were introduced in Rebirth and everyone realized that the "troll engine" was nothing more than RNG messing with their heads.

In retrospective, it should've been obvious that something like this wasn't real, but a part of me still wishes that it was.
Last edited by Danizk0; Dec 4, 2021 @ 6:52pm
Danizk0 Dec 4, 2021 @ 7:01pm 
And since I already started talking about playground rumors, I only recently discovered for myself that you don't have to spend all available money/health on beggars in one go. One time I heard that they "forget" how much you gave them once you leave the room and that belief got stuck in my head for 9 whole years!
Last edited by Danizk0; Dec 4, 2021 @ 7:03pm
HeyThere Dec 5, 2021 @ 9:06am 
Does anyone know if the Luck attribute affects these specific chances? I don't think they should, but for some reason they might
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Date Posted: Dec 4, 2021 @ 8:45am
Posts: 23