Editing Guides/Probability (section)

== Basic considerations ==
There underlying problem in determining probabilities and related values is classically an [http://en.wikipedia.org/wiki/Urn_problem Urn problem]: Let's say, the chance for an item to break is 1 in 300 (uses, hits). Imagine an urn with 299 white marbles and 1 black marble. Take a marble from the urn, look at it and put it back in. Now, the chance to pick the black marble is obviously 1 in 300, thus the urn models our problem.

The Eternal Lands server does exactly the same thing as picking up a marble, looking at it and putting in back when determining if your item breaks during this use/hit. Of course, the server doesn't need the visual aid, a 5% chance (5 in 100 equals 1 in 20) is computed like this
 if(my_rand(19)==2)
according to [http://www.eternal-lands.com/forum/index.php?s=&showtopic=39550&view=findpost&p=408808 Entropy] (please note that the above link talks of a 5% chance for a 20 instead of 19, however Entropy corrects himself [http://www.eternal-lands.com/forum/index.php?s=&showtopic=39550&view=findpost&p=408818 later] in the same thread, this is due to the fact that the zero is included, making 0..19 20 numbers), this checks if a randomly generated number equals 2 (the black marble).

Now, you'll probably want to use your items more than once which leads us to the next section: