I need some math help.

[Yvresse]

I'm trying to calculate something.

If I have an 80% chance to succeed at gathering an item.

I know each roll is individual. So just having 80% doesn't mean I'm going to roll 8 successful and 2 fails.

So how do I calculate this?

So let's say I have a base 80% success rate. But I mine and fail 7 times, and succeed 3.

How can I calculate the odds of that happening? There must be a formula or something.

Thanks.

Sorry, I'm really not so good at math.

[Illmaeran]

Every single "hit" has an 80 percent chance of succeeding so on average 80 out of 100 hits will be successful. That being said, I've had times where I've hit HQ items three times in a row on 10% chance and times when I've missed multiples in a row on 95+%.

If you're trying to figure out how many nodes you need to mine in order to get a certain quantity of items, best of luck to you. That is the path to madness. . You're best off just gathering until you've got the number you want.

If you REALLY want to take an educated guess at how many nodes you'll need to gather, figure out what the number would be at your raw % then give yourself a buffer of an extra 5 nodes.

For example, if I wanted to gather 100 crystals from nodes with 4 attempts apiece with an 80% gather rate I'd calculate this:

100%/20% = 5
100/4 = 25
25 + 5 = 30

[Jojoya]

Someone trained in statistical math could probably share the formula with you for determining the probability of certain success or failure conditions happening.

It's pretty pointless to apply to things that happen in video games, though. They don't use true RNG, they use pseudo-RNG that's affected by "seeds" and some of the seeds used in games are terrible.

[Frizze]

If youre asking for the formula to see just how unfortunate you were on these 10 swings, you got fairly unlucky. The odds of getting 7 or more fails in 10 tries should be about .00086 if i remember how to calculate these right. If youre asking because you think this in some way proves that the percentages shown are false or that the rng for the game is broken, then i hate to tell you that your data shows no such thing. Your data actually shows nothing at all, as 10 swings is not even remotely close to enough data to start approximating these things. This topic comes up periodically on the boards, and the answer is that the rng solution they use for the game is a good one. There was a post a couple years ago where one of the devs went into depth about it, and im sure someone can dig it up if you want to read it. But as with any rng approach that is supposed to be fairly random, any given short string of trials could be a streaky one. And because of the human tendency to remember the negative outcomes more then the positive ones(ever get a HQ craft without putting in any quality steps? or that 20% ore hitting 3 times in a row?), this has been debated repeatedly. Several people over the years have been convinced enough that they were right and math was wrong that they set out to run a large enough sample of tests(a dev could ask for a readout of the last x million trials to make sure the numbers are about right, an individual looking to replicate this would likely want to go 1000+ times and keep good notes) to prove their point. Most never come back with the results of their work(either because they never actually did it or because they didnt want to admit that their data proved them wrong is what i would guess), though one or two did in fact ultimately agree that the long-term averages were about right.

[Naoki34]

I'm trying to calculate something.

If I have an 80% chance to succeed at gathering an item.

I know each roll is individual. So just having 80% doesn't mean I'm going to roll 8 successful and 2 fails.

So how do I calculate this?

So let's say I have a base 80% success rate. But I mine and fail 7 times, and succeed 3.

How can I calculate the odds of that happening? There must be a formula or something.

Thanks.

Sorry, I'm really not so good at math.

If you have an 80% chance, you have a 20% miss, you can have a 99% chance, you can also miss and even at 99.99... % too, by the way.
At each move, a dice of 100 is rolled, like in Paper Role Playing.

It's no more complicated than that.

Just like crafting, if you have 99% to make a HQ, you can very well fail and have a NM. But you still have a better chance to succeed.

It's not about math, it's about percentage luck.

[MilkieTea]

Think of it like a coin flip - you have a 50/50 (50%) chance of getting either heads or tails, but this doesn't mean you'll get heads always 50% of the time - you might go 20 or 30 flips with only tails.

[DrWho2010]

read up on this - https://en.wikipedia.org/wiki/Mersenne_Twister

if you can understand this then you'd understand rng in this game.