I was trying to find or make a function which is not equi-probable, meaning some values are less probable than others. Apparently what I want has something to deal with <http://en.wikipedia.org/wiki/Normal_distribution> and Gaussian Distributions.

The math and algorithmics involved in such a function seemed a little complex, and I was not sure if they were really necessary.

My goal is to make better loot more rare to get (the player can generate an infinite amount of loot events), but since I want the loot quality to be expressed with a single value, I need a function that returns values > 0.9 very rarely but will return value > 0.1 much more often.

I tried `log((100*random())^(0.01*random()))` ('^' meaning exponent, so '\*\*' to be precise) in python, I got results that seems pretty satisfying, but I'm really suspicious that I can can trust those results.

Is there some type of standard function that already do what I'm looking for ? Do you think this formula is somehow reliable ?

I don't want to have "loot tables" because they're integral values, and it would require more tweaking, and I don't intend to have special items that are much more powerful than lower tier items.

Here are the results, with 10000 picks:

```
('0.003', 1514, '15%', '####################')
('0.006', 1323, '13%', '#################')
('0.010', 1269, '12%', '################')
('0.014', 1169, '11%', '###############')
('0.022', 1187, '11%', '###############')
('0.027', 1089, '10%', '##############')
('0.028', 964, '9%', '############')
('0.034', 760, '7%', '##########')
('0.037', 496, '4%', '######')
('0.043', 228, '2%', '###')

```