Random number..percentage?

Hi guys, weird question here that I'm hoping someone might be able to help me with.

Is there a way to assign a random number...with a certain number having a higher percentage of being assigned than other numbers?

Here's an example:

I have a player sprite, I also have an enemy sprite. When the enemy sprite collides with the player (physics objects btw) I want to subtract say, 20 from the player's health variable.

That's easy enough to do, but I would LIKE to have the damage be more randomized than that. Anywhere from having 10-20 health subtracted...but for the most part I want -20 health to be assigned on average with the 10-19 range only showing up on occasion.

Oi, did I explain that well enough? =

Maybe something like:

Enemy >

      On collision with player >

                               Subtract 20 from Healthvar...but sometimes 10-19 :P

Thanks everyone.

Global Variable DAMAGE

On collision with player: Set DAMAGE to int(random(100))

   If DAMAGE > 0 and DAMAGE <= 80 then - 20 from health.

   If DAMAGE > 81 then - int(random(10,20)

80 percent chance to get 20

20 percent chance to get 10-19

Brilliant!

Works perfectly, thanks a ton! :)

Using ArcadEd logic, you could fit all of it in a single expression.

On collision with player: Set DAMAGE to (random(100) <= 80) ? 20 : int(random(10,20))