This topic first introduces the basic concept of probability.

Lesson 1 of 3: Learning Outcomes

Learning Outcomes.jpg

At the end of this lesson, you should be able to

describe a probability event by listing all the possible outcomes in that event

Lesson 2 of 3: Introduction to Probability (10 mins)

What is a Probability?

A probability is a number that reflects the chance or likelihood that a particular event will occur. Probabilities can be expressed as proportions that range from 0 to 1, and they can also be expressed as percentages ranging from 0% to 100%.

Terms used in Probability

Terms	Description
Event	Each possible outcome of a variable.
Joint Event	An event with 2 or more characteristics
Complement	A complement of event A includes all events which are not part of A
Sample Space	Collection of all possible events

In an experiment, if each outcome in the sample space is equally likely to happen, for an event E:

Outcome Formula.jpg

Example:

An unbiased coin is tossed three times, list out the sample space and the event in which there is exactly one head.

Sample Space
Events

Important Notes:

Probability of an Event E is between 0 and 1, inclusive
Sum of all Probabilities with simple events for an experiment is always 1
Complementary Event: A complementary event E’ is the set of all outcomes in a sample space that is not included in Event E