# 5: Basic Concepts of Probability

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##### Learning Objectives

Develop the students:

• ability to do the counting
• probabilistic reasoning

Thinking out Loud

What do we mean if we say that the probability of tossing a coin and seeing a head is about 0.5 (50% or the odds are 50/50)?

One possible answer: We are claiming that if you toss the coin in question a large number of times then you should see heads appearing about half of the time.

Thinking out loud

What do people mean when they refer to a "100-year" flood?

One possible answer: They are claiming that the likelihood of a flood of that magnitude happening in any given year is 0.01 (1%, or the odds are 1/100).

## Contributor

This page titled 5: Basic Concepts of Probability is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Pamini Thangarajah.