This is incorrect.
You are grossly abusing any math terminology and very lacking in even basic understanding of the theory of probability.
What you are discussing is a
discrete uniform distribution. That is, in a discrete uniform distribution, the probability of an event, P(E), is the # of elements in the event (the event E being a subset of the sample space S) divided by the total number of elements in the sample space S.
That is, if you have 4 marbles and one is chosen at random, the probability that the marble is green (if one is red, one is blue, and 2 are green), defines the event that you choose a green marble, and since E describes 2 marbles, the probability is |E|/|S| = 2/4 = 1/2.
The problem is that when deciding how to give a prize in a video game, you do not make a list of all prizes then randomly pick out of those which to give the player. What you do is define how rare you want an event or prize to be, and use a random number generator with the probability distribution in mind that would give you the ability to select which event should happen.
For instance, in computing your damage, it may be realized by the developers that you should be more likely to achieve a damage near the average of your min and max damage, and much less likely to deal damage near the max of your attack power and equally as unlikley to deal damage near the minimum.
So what they may do is use a normal distribution with an expected value of the average of your min and max attack with a fitting standard deviation to set the probability of hitting near your min and max as they wish.
You might want to get a book on the theory of probability if you want to know more about random variables and their distributions, and how these CAN distribute choices over non-uniform cases like this. Yes, it *IS* random, it's just a little over your head.