A sick math problem I can't seem to wrap my brain around.

[magnetaress]

An 8% chance every 90 minutes.

vs

An 1% chance every 6 minutes.

8/90 = 0.0888888888888889% chance per minute?

and

1/6 = 0.1666666666666667% chance per minute?

How insane on a scale of 1-10 is this math? :o :p

[Videri]

If we're talking about killing NPCs here, don't forget that killing an NPC takes some amount of time, however small. This will affect the 6-minute spawn much more than it affects the 90-minute spawn since you'd be killing 1 NPC every 6 minutes, as opposed to killing 1 NPC every 90 minutes.

Does it make sense to calculate the chance per minute for EverQuest? Maybe it would be more useful to calculate the chance per hour.

Are there any 6-minute spawns, or are they all 6:40?

Also, I don't know of any 90-minute spawns. There are at least two 2-hour spawns in Rathe Mountains and a lot in Kedge Keep. Is there a particular one you're thinking of?

[magnetaress]

S Ro AC vs OOT AC

Everyone on my server says just afk in S Ro, I want exp so I am camping where I get exp...

I can kill one every 9 minutes...

so 1/9?

%0.1111111111111111‬ x 60? = %6.67 perm minute? or, .11 percent per hr

vs

8/90 = 0.0888888888888889% chance per minute?

So potentially 11 hrs for 100% drop. Vs potentially 88 hrs for 100%?

We are likely looking more at the mean, so more likely 6-7 hrs vs 40-50 hrs.

I can confirm, that this thing spawns 6 minutes after I kill it.

[agnostic]

The SRo AC has a small chance to spawn right before 9pm gametime, just park the character you'll want to kill it in the desert area and play an alt for awhile, camp over when it's 8pm gametime and see if it spawns.

[magnetaress]

The SRo AC has a small chance to spawn right before 9pm gametime, just park the character you'll want to kill it in the desert area and play an alt for awhile, camp over when it's 8pm gametime and see if it spawns.

how does this even work on blue when 5 wizards at lvl 50 log in and begin casting ice comments?

Anyway, not going to happen until this character becomes an alt, I am forumquesting and talking to guildmates actively, so killing a cyclobro ever 9 for a 1% chance at a kewlcyclobro is what I am doing.

[magnetaress]

My maths were accurate it took 6 hrs of poopsock'n to get a ring )

[Gustoo]

In sro?

Good work

I haven't got the ring since they changed up the PH's in sro for AC. Never got the OOT AC but I thought he was way easier.

[Swish]

how does this even work on blue when 5 wizards at lvl 50 log in and begin casting ice comments?

Anyway, not going to happen until this character becomes an alt, I am forumquesting and talking to guildmates actively, so killing a cyclobro ever 9 for a 1% chance at a kewlcyclobro is what I am doing.

Ice comments are the best comments.

[Videri]

So potentially 11 hrs for 100% drop. Vs potentially 88 hrs for 100%?

We are likely looking more at the mean, so more likely 6-7 hrs vs 40-50 hrs.

Yes, we are definitely looking at the mean. There is never a 100% chance of something dropping in a given time period.

Beware the Gambler’s Fallacy: the idea that previous outcomes influence future outcomes.

Suppose you flipped a coin 99 times and it came up heads every time. What is the likelihood of tails on the next flip? 50/50.

Suppose you camped a mob with a 10% chance to spawn and got 9 placeholders. What is the likelihood of a named on the next pop? 10%.

A lot of people at the manastone camp didn’t understand this, or refused to accept it. Past outcomes do not change the odds of a future outcome, ever.

[magnetaress]

Ice comments are the best comments.

Yes, they are.

@gustoo it took 6.5 hrs in OoT, was pretty close. Know how RNG can be though, could get it in 3 or 23 if real bad luck.

[Dogma]

Took me over 600 hours camping Jail in KC before I got my first Tstaff drop. That's only counting actual hours camping it tho. I haven't tried keeping track since.

Got a few leveling on random toons in the zone and a few logging in drunk at 2am just wandering around.

Then again I was randomly given a Spirit Wracked Urn for free also. So idk. Luck is weird.

Be good, hope for the best and be okay when it isn't. Bout all you can do.

[Ruien]

The OP seems to be asking how to calculate the number of attempts at a mob before getting at least N drops, given a drop rate.
That is the cumulative distribution function (CDF) of a negative binomial distribution (https://en.wikipedia.org/wiki/Negative_binomial_distribution). Scilab (https://www.scilab.org/) has this as the cdfnbn (https://help.scilab.org/docs/6.1.0/en_US/cdfnbn.html) function.

This gives us the number of failures before a certain number of successes. The total number of attempts is the sum of the failures and successes.

For example, if we want 3 drops at 8% success per attempt, then it will require 48 attempts to be 75% sure of getting them:

successes = 3
success_chance = 0.08
confidence = 0.75
attempts = successes + cdfnbn("S", successes, success_chance, 1.0-success_chance, confidence, 1.0-confidence)

attempts = 48.031623

If the average time between attempts (including fighting) is 90 minutes, then this will require 72 hours. To be 95% sure, it increases to 77 attempts (115.5 hours).

If we want 3 drops at 1% success per attempt, then it will require 391 attempts to be 75% sure of getting them:

successes = 3
success_chance = 0.01
confidence = 0.75
attempts = successes + cdfnbn("S", successes, success_chance, 1.0-success_chance, confidence, 1.0-confidence)

attempts = 391.07841

If the average time between attempts (including fighting) is 6 minutes, then this will require 39.1 hours. To be 95% sure, it increases to 628 attempts (62.8 hours).

A few results:

1% chance, 1 success, 50% confidence: 69 attempts
1% chance, 1 success, 75% confidence: 138 attempts
1% chance, 1 success, 95% confidence: 298 attempts
1% chance, 1 success, 99% confidence: 458 attempts

5% chance, 1 success, 50% confidence: 14 attempts
5% chance, 1 success, 75% confidence: 27 attempts
5% chance, 1 success, 95% confidence: 58 attempts
5% chance, 1 success, 99% confidence: 90 attempts

10% chance, 1 success, 50% confidence: 7 attempts
10% chance, 1 success, 75% confidence: 13 attempts
10% chance, 1 success, 95% confidence: 28 attempts
10% chance, 1 success, 99% confidence: 44 attempts


This is sort of off the top of my head; it might be wrong. Can anyone confirm?

[magnetaress]

Took me over 600 hours camping Jail in KC before I got my first Tstaff drop. That's only counting actual hours camping it tho. I haven't tried keeping track since.

Got a few leveling on random toons in the zone and a few logging in drunk at 2am just wandering around.

Then again I was randomly given a Spirit Wracked Urn for free also. So idk. Luck is weird.

Be good, hope for the best and be okay when it isn't. Bout all you can do.

The OP seems to be asking how to calculate the number of attempts at a mob before getting at least N drops, given a drop rate.
That is the cumulative distribution function (CDF) of a negative binomial distribution (https://en.wikipedia.org/wiki/Negative_binomial_distribution). Scilab (https://www.scilab.org/) has this as the cdfnbn (https://help.scilab.org/docs/6.1.0/en_US/cdfnbn.html) function.

This gives us the number of failures before a certain number of successes. The total number of attempts is the sum of the failures and successes.

For example, if we want 3 drops at 8% success per attempt, then it will require 48 attempts to be 75% sure of getting them:

successes = 3
success_chance = 0.08
confidence = 0.75
attempts = successes + cdfnbn("S", successes, success_chance, 1.0-success_chance, confidence, 1.0-confidence)

attempts = 48.031623

If the average time between attempts (including fighting) is 90 minutes, then this will require 72 hours. To be 95% sure, it increases to 77 attempts (115.5 hours).

If we want 3 drops at 1% success per attempt, then it will require 391 attempts to be 75% sure of getting them:

successes = 3
success_chance = 0.01
confidence = 0.75
attempts = successes + cdfnbn("S", successes, success_chance, 1.0-success_chance, confidence, 1.0-confidence)

attempts = 391.07841

If the average time between attempts (including fighting) is 6 minutes, then this will require 39.1 hours. To be 95% sure, it increases to 628 attempts (62.8 hours).

A few results:

1% chance, 1 success, 50% confidence: 69 attempts
1% chance, 1 success, 75% confidence: 138 attempts
1% chance, 1 success, 95% confidence: 298 attempts
1% chance, 1 success, 99% confidence: 458 attempts

5% chance, 1 success, 50% confidence: 14 attempts
5% chance, 1 success, 75% confidence: 27 attempts
5% chance, 1 success, 95% confidence: 58 attempts
5% chance, 1 success, 99% confidence: 90 attempts

10% chance, 1 success, 50% confidence: 7 attempts
10% chance, 1 success, 75% confidence: 13 attempts
10% chance, 1 success, 95% confidence: 28 attempts
10% chance, 1 success, 99% confidence: 44 attempts


This is sort of off the top of my head; it might be wrong. Can anyone confirm?

These posts are so awesome and I have total and absolute faith in them.

And ya, nothing is certain. So it's possible to never ever get an AC ring. (scary)

Thank you so much for the lengthy math explanation. That is what I was most curious about. I have a very hard time understanding that stuff, and my math teach gave me a passing grade by 1 point because she just didn't want to ever see me again. So I greatly appreciate you taking the time to try and teach me.

[Topgunben]

An 8% chance every 90 minutes.

vs

An 1% chance every 6 minutes.

8/90 = 0.0888888888888889% chance per minute?

and

1/6 = 0.1666666666666667% chance per minute?

How insane on a scale of 1-10 is this math? :o :p

Here's the crazy thing my man:

8% chance over 90 minutes not so good.

So lets say you really want that item that has that % of chance to drop over that amount of time.

Well, even after 15 hours of camping said item, you still have a 43.4% chance that the item will not have dropped. (.92^10) = .434 & ((10 x 90)/60) = 15

After 30 hours, there is still a 18.8% chance the item will not have dropped.

After 60 hours of poopsocking, there is still a 3.56% chance the item will not drop.

It's this type of analysis that keeps most sane people from trying too hard to compete at the upper levels.

[magnetaress]

Here's the crazy thing my man:

8% chance over 90 minutes not so good.

So lets say you really want that item that has that % of chance to drop over that amount of time.

Well, even after 15 hours of camping said item, you still have a 43.4% chance that the item will not have dropped. (.92^10) = .434 & ((10 x 90)/60) = 15

After 30 hours, there is still a 18.8% chance the item will not have dropped.

After 60 hours of poopsocking, there is still a 3.56% chance the item will not drop.

It's this type of analysis that keeps most sane people from trying too hard to compete at the upper levels.

Ya.

The EQ gods smiled at me when I logged in, I was running my wiz to lake rathe to get her bone rod from the skele dudes for her clicky debuff staff...

Low and behold AC was up and roaming, LUCK.

I try not to camp these things, I camped it on my necro cuz I definately wanted to do this for msyelf, and i didnt mind if it took days. Glad I wasn't pvpd out of oot otherwise I may have QQ'd or played an alt.

Again, Luck, who knows. I feel good, and I feel more resilient toward these camps now. I guess my best advice is dont get your heart set... on something in a specific time frame, give it space to come when it comes. Or allow urself to farm the plat for an MQ. Thats what its there for!