[Math] Probability of entering Beta

[DISCLAIMER]This post is outdated, and reflects values from August 2011, when the beta began.[/DISCLAIMER]

Why, hello there!

I calculated a few probabilities for your enjoyment.

Assuming there are 50,000 registered accounts, that forum posters have ten times more chances of being picked for the beta and that new players are picked every 15 minutes, we have these basic probabilities:

- Probability you will be picked on the next tick:
1/95,000 if you don't post of the forums;
1/9,500 if you do.

- Probability you will be picked today:
0.9% if you post on the forums;
0.1% if you don't.

- Probability you will be picked this week:
7.1% if you post on the forums;
0.6% if you don't.

- Probability you will be picked in the next two weeks:
13.74% if you post on the forums;
1.34% if you don't.

- Probability you will be picked this month:
25.6% if you post on the forums;
2.65% if you don't.

- Probability you will be picked in the next 3 months:
58.81% if you post on the forums;
7.75% if you don't.

This is, of course, assuming the 15-minute timer won't change over the next 3 months, which is highly unlikely.

The underlying math:
I'll explain how I obtained the values for the probability of getting picked today, if you're a forum poster.
We have a series of 96 trials, with a 1/9,500 probability of success on each trial. Then we are looking for the probability of NOT having 0 successes. In other words, let X be the number of times you will be picked today. Then we are looking for P(X>0). X follows a binomial distribution of parameters 96 and 1/9,500. So we're looking for 1-P(X=0), which, in this case, is 0.9%.

[Edit] Changed the base probabilities from 1/5,000 to 1/9,500 for forum posters and 1/50,000 to 1/95,000 for forum lurkers based on:

"

FinalParagon wrote:

Let's go with [the] assumption at any given time there are 50,000 accounts not in the beta and 10% of those (from one of your posts a few pages back) have posted in the forum (so 5,000), with every person picked replaced by a new person of the same category over time. For the purpose of probability, the posters actually count as 10 people, or a total of 50,000 vs. the 45,000 who haven't posted. The pool of names they pick from actually contains 95,000 names, even though only 50,000 of them are
unique.

So the probability of a non-poster is 1/95000, where the probability of a poster is 1/9500 given the numbers [we're] using.

[Edit #2]
Adjusted values for the new 15-minute timer.

You mean I gotta wait 3 months for a beta invite?!
Omfg my world just came crashing down and I think I'm going to have a heart attack now!

Its summer why are you doing math now school doesn't start for at least another month.

"

Fourier wrote:

- Probability you will be picked on the next tick:
1/50,000 if you don't post of the forums;
1/5,000 if you do.

Not exactly. Chris said forum users are 10 times more likely to get invited (from whatever the previous value was) not compared to non forum users.

This math definitely makes me want to turn away from the timer, but I can't!

Nicely done, sir.

Magnificent.

"

Drb00 wrote:

You mean I gotta wait 3 months for a beta invite?!
Omfg my world just came crashing down and I think I'm going to have a heart attack now!

Its summer why are you doing math now school doesn't start for at least another month.

Well, I should add that I didn't consider a growth or decrease of the total registered accounts through time.

I always consider the timer will pick a player from a pool of 50,000. In 3 months, there might be a lot more members than there are today.

i received an invite to test SWTOR... i dont want SWTOR damnit i want PoE!

if i see a penny and pick it up does that increase my odds...

Awesome ! Can't wait!