1. Originally Posted by Niku
So I am currently farming for the Drake of the North Wind in Vortex Pinnacle and I have cleared the place 77 times since I started counting.
The drop chance is 0.78% according to wowhead and I'll trust that it's either that or close to it. I'm using this article http://wow.joystiq.com/2010/01/13/dr...ity/#continued to calculate the probability for the mount to have dropped during the course of my 77 runs (at the moment: 45.28075 percent). But seeing as I am not even remotely talented when it comes to mathematics, my mind is having an issue wrapping itself around the whole ordeal.

Everytime I kill the dragon the drop rate is it's fixed 0.78%, that does not rise or fall on any new kill. On the other hand, the number of times I have killed him rises and I should have had an overall increase chance for it to have dropped... so should I get more excited about the next run and the run after that? The drop rate is unchanged, but it feels as if I have a higher chance to get it everytime... but I don't.
When I am at 500 runs and let's assume for arguments sake I have not had it drop yet, the chance that I would have seen it within the number of my runs is now at 98%. In such a scenario, should I expect it to drop any run now? Or is that foolish since the probability is still 0.78% which doesn't seem promising at all.

Ultimately I don't know what to ask. I believe it boils down to "Should I get more excited since it's more likely to drop?".
The probability per drop remains the same. You aren't any more likely than you ever were.

This is the part that's 45%, so pay attention, it's fairly simple.

The odds that you'll have done it 77 times without seeing a drop are (according to that site, apparently, i don't have the patience to do the math at this point) about 55%. So, in a sample of 1000 people, around 550 will have not seen it after 77 attempts. Each time that you do it, the likelihood that you will see it becomes higher not per attempt but in the entire sample of your attempts.

In other words, it starts being really unlikely that you haven't seen it after a few hundred tries. That doesn't affect drop rates in any way, but it means that your probability of having seen it in x attempts, including this attempt will be higher. This is why trying a bunch of times will get it for most people.

One of the things about WoW that's unfortunate is, in 7 million players, there's like a .00001% chance that even doing it 100,000 times will never see it. Which, while it seems meaningless, is 70 people. So, probability states that about 70 people will never get it even if they do it once a day for the next 273 years.

Functionally, this means that even with very high drop rates, anything that has a random drop chance is, statistically, impossible for all players to get. In fact, a fair number of people (approximately equal to most people's total 'friends they've ever made in a lifetime' amount) will almost certainly have no chance to ever get it.

RNG adds excitement to the game, but always understand that it's existence means you may be one of the 70 people (from my example, it's actually a higher or possibly lower number depending on droprates) who will, after 273 years, never see it.

Therefore, be happy if you see it, because you could have been one of those 70 At least that's how I try to look at it.

- - - Updated - - -

Wow, just saw a lot of people with seemingly little math education arguing pointlessly.

Let me try to explain something here.

Your chance for this mount to drop is (according to existing data) about .78%.

No matter how many times you kill it, your chance to get it on that kill will still be .78%.

Your likelihood of getting it from any given kill will never increase (except eventually Blizzard will probably raise it to 2-3%, most things eventually have) above .78%

However.

If 100 players kill the boss one time, the statistical likelihood that one of them will have gotten it nears 100%.

Now: what does this mean, and what does it not mean.

IT DOES NOT MEAN:

That you are more likely to get it.
That you are "due" a drop.
That it has to drop eventually or otherwise it won't actually be .78%.

IT DOES MEAN:

That your chance to be a member of the group "In the extremely small group of people for whom it didn't drop at least once out of 100 chances" is very small.

Now, to further this point.

You _still_ aren't any more likely to get the mount than you were before, because like someone said, you can't factor past events into probabilities for the future. Why? Because the chance of me waking up on November 18, 2013 is 100%. It already happened. That quantum state in this matterverse has already collapsed into a stable wavefront and is no longer accessible from my position in relative spacetime. It no longer has a probability. The cat is now either alive or dead. It is no longer a probabilistic event; "LurkerOnly wakes up on November 18, 2013" is, from my perspective, a collapsed event that is no longer accessible and can only be observed. It is 'actual'. I'm sorry, I know that this will completely cause some of you to think "this guy is insane", but this is just general relativity, 100 years old theories.

So, like I said. Remember that, in terms of probability, there is nearly 100% chance that out of 7 million subscribers trying once a day for 30 years, one person will never see it drop. That person could be you. Just be happy if you see it, and don't let your disappointment increase each time it doesn't drop.

In a very real sense, the next time you kill the boss and try to get the mount, will be the first time you've ever done it. Try to approach it with the same hope but understanding of its unlikelihood, and don't get too bummed out if you don't see it. .78% is kind of a low chance, after all.

2. Originally Posted by Daedelus
Wrong. Wrong. Wrong.

If you flip a coin 99 times and get heads every time, what is the probability of you getting tails on the 100th flip?
You are misunderstanding how to use probability with multiple attempts. It's not the individual attempt probablility that is in question. It's the cumulative probablility.

Example: Coin flipping. Pretend Heads = Getting Mount. Tails = Not getting Mount. What is more likely to happen?
A) Getting a Heads in 1 flip
B) Getting a Heads in 5 flips

From your description, the chance of both A and B happening are exactly the same since each indidivudal attempt is a 50% chance.

Well, let's prove what really happens. Try flipping a coin until you get Heads. Repeat that 5000 times. You will see that A happens much less than B. This will happen every single time you do it.

Now, for clarification, this is not a linear relationship. There will never be a 100% chance of getting Heads or Tails. But your chance of "not getting Heads" 100x in a row is low.

3. Originally Posted by voidspark
I advise you to study more probability if you wish to come off as an "expert" but I understand if you give up. It's not for everyone

Here's another justification which could help you "understand" if that is even possible (you don't seem to have a desire to read anything I write): There is a reason I said the next 458 runs, and did not give him credit for the ~40-50 runs he previously did already.

I really love you voidspark, i struggled with this and me and a much more educated friend discussed this, i get it now, after like 50 nights of drinking and arguing about it
(friendly arguing is what we do) .

4. The probability to drop at the x-th try is (1-0.0078)^(x-1) * 0.0078

The propability to drop before(or at) the t-th try is 1-(1-0.0078)^t

The probability to drop after the t-th try is (1-0.0078)^t

The probability to have dropped before(or at) the 77th try is 1-(1-0.0078)^77 which is almost equal to 0.4528=45.28%.

"Expect" it to drop around the 128th try (1/0.0078=128.205128205) but this may vary A LOT!, because the standard deviation is the square root of (1-0.0078)/0.0078^2 which is around 127.7.
You can observe that, if you go down at the very end of the graph page that I have linked bellow and see the Random sample from the distribution section and check the numbers. They are a MESS, they are not near at the "expected" 128! Almost completely random!
Thus, EXPECT NOTHING.

http://en.wikipedia.org/wiki/Bernoulli_trial
http://en.wikipedia.org/wiki/Probabi...probability.29
http://en.wikipedia.org/wiki/Geometric_distribution (this is the distribution that our events follow)
Graph(look where it says Plot of CDF at the end of the page): http://www.wolframalpha.com/input/?i...078&lk=4&num=3

5. Just an update guys. Got it a few seconds ago on my 109th run.

6. Originally Posted by Niku
Just an update guys. Got it a few seconds ago on my 109th run.
Which is well around the amount of runs you'd expect to get it in

Grats

7. Originally Posted by voidspark
Which is well around the amount of runs you'd expect to get it in

Grats
Thank you!

8. Originally Posted by Niku
Just an update guys. Got it a few seconds ago on my 109th run.
Grats!
(Well, not that far away from 128 :P)

9. the funny thing is that this thread wasnt needed at all since its explained the on the calculator webpage itself

10. The best part of this thread was watching several people - all saying largely the same thing in essence in most cases - arguing and calling each other wrong because their understanding didn't quite extend to alternate explanations of the same concept.

11. Probability for gamers. No matter how many times you run something, no matter what you do, or how many times you've already done it, the numbers don't change. It will always be less than a 1% chance. Run it 5 times an hour every day till the sun explodes, and it's still a 1% chance to drop. You're committing the gambler's fallacy, basically. Most players do. That's how they keep you hooked. "But I've run it 700 times, it's bound to drop this time." No. No, it's not. It is the exact same 1% drop rate as the first time you ran it. Probability is theoretical, not practical. Besides probability has nothing to do with Blizzard's "fun" RNG.

12. Originally Posted by voidspark
Wowhead frequently seems to reset their data (for instance, when drop-rates change) which means their sample sizes are often not as large as people think. Also with such a low drop rate to begin with, I believe the data is far more error prone (for instance, getting 1 drop versus 2 drops out of hundreds of tries will change the rate a lot!). I'm not great at statistics though, would have to crunch numbers so I can't say for sure if that's right.

- Case in point, if you look at their regular items, you'd think each would have a ~20% drop rate based on logic and the Heroic data (it picks one of 5 items on the table to give you all with equal weight). It seems in the Normal mode data things are a bit fishy with that Leather mantle.
True however in this case it's 1654/212203.

Originally Posted by voidspark
That is definitely not true, I got at least 3 Azure Drakes (don't ask why I ever went back to Malygos).
Yeah but some items work differently to others. It's possible is all I'm saying, unless someone can confirm seeing two.

13. I am describing the chance of him NOT getting it after X consecutive runs. That means that it is still a possibility he will never get it but his chances will be higher to get it THAN not get it after the 619th run (assuming wowhead is right)

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