Hi, I'm not sure if I made up a new word. But here's what I'm after:

I want to generate a random value for a bunch of sprite's (0-100) which is easy, but the thing that has stumped me is, I want to make the high value more rare. So you could easily find sprites with random of 0-10 but would have to search a long time for 90-100.

I know I could event out every factor of 10 or some thing like that, but does anyone know if there's an easy way to do this?

You could take the sqaure root of random number then round it, this will make lower numbers rarer, but you could minus that value from 100 so that higher values are rarer.

100 - (round(random(10000)^0.5))

or you could make it even harder to get 100

100 - (round(random(1000000)^0.33))

That works for me, don't know if thats the best way to do it though.

So say your mean is 10, and the sigma is 10 you will get any random number between 10-10, and 10+10....

Kind of, but sigma is just the width of the bell curve. Specifying 10 doesn't actually mean it will give you a number that's either ten greater or ten less. Here, I made this .cap. A sigma of 4 gives you around about a 32 number deviation from the mean with normally distributed probabilities. Any number is actually possible, but the chance is really small. You should clamp the value if you want it to stay within a certain range.

The math geek in me forced me to register just to answer this question.

There's a really simple way to get almost exactly what you're after: For every random value you need, generate two random values and pick the lowest. For values of 1-100, that should give you:

Just tested this out and it works pretty good, with the exception that the number 100 will never be returned because your always choosing the lower value.