CHAPTER18 Probability
In This Chapter
- The basics of counting
- Permutations and
combinations - How to find the probabil-
ity of an event - Probabilities when more
than one event occurs
Math is all about the one right answer, right? Not so fast. It
would be comfortable if everything had an absolutely certain
right answer, but that’s often not the case. One of the greatest
skills math gives us is the ability to talk about possibility and
uncertainty in an organized way. When you can’t be certain
that something is going to happen, being able to talk the
chance of it happening and being able to assign a number to
that chance is helpful.
In this chapter, you’ll explore ways to assign a number to
the likelihood that something will happen. You’ll do that
by comparing to all the things that could happen. In simple
situations, that’s all you need to do, but you’ll see there are
some rules to make the more complicated situations easier to
handle. For all of this, you’ll have to do a lot of counting, so
let’s start with a look at efficient methods of counting.