ABSTRACT
In Chapter 1, you might have wondered about all the capital and lowercase letters. When do you use one versus the other? The answer is simple: Uppercase letters denote random variables, and lowercase letters denote ’xedquantities. Think of what you will see, or could see, or might have seen versus what you actually do see. If you don’t actually see something, it is variable in your mind and hence modeled as a random variable. If you actually see it, it is Ÿxed or nonrandom.
