You can have discrete random variables, or continuous.

你可以有离散的随机变量，也可以是连续的。

You have discrete, so finite meaning you can't have an infinite number of values for a discrete random variable.

你有离散的，所以有限意味着你不能为离散随机变量拥有无限数量的值。

Well, based on how we thought about the probability distribution functions for the discrete random variable, you'd say OK, let's see.

好吧，根据我们对离散随机变量的概率分布函数的看法， 你会说好吧， 让我们看看。

So it's important to realize that a probability distribution function, in this case for a discrete random variable, they all have to add up to 1.

所以重要的是要认识到概率分布函数，在这种情况下对于离散随机变量， 它们都必须加起来为 1。