# Chapter 5: Probability

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In Chapter 5, we step away from data for a while. We take a look at a new topic for us - **probability**. Most of us have an idea already of what probability is, but we'll spend quite a while exploring different probability experiments (like rolling two dice) and investigating the different outcomes.

We'll learn several different rules, ranging from the probability that at least one of two events occurs in Section 5.2 (the Addition Rule), to the probability that both occur in Section 5.3 (the Multiplication Rule), to the probability that one occurs if we know the first has already occurred in Section 5.4 (conditional probability).

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In Section 5.5, we learn some new counting techniques that'll help us answer questions like "How many 4-digit garage door codes are possible if digits can't be repeated once used?"

Section 5.6 brings it all together, and helps you choose which strategy to apply.

If you're ready to begin, just click on the "start" link below, or one of the section links on the left.