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Probability Basics

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Understanding Probability
Learn the fundamental concepts of probability theory.

Probability is a measure of the likelihood that an event will occur. It is quantified as a number between 0 and 1, where 0 indicates impossibility and 1 indicates certainty.

Basic Probability Formula:

P(Event) = Number of favorable outcomes / Total number of possible outcomes

This formula applies when all outcomes are equally likely.

Key Probability Concepts:

Sample Space

The set of all possible outcomes of an experiment.

Example: When rolling a die, the sample space is 6.

Event

A subset of the sample space.

Example: Rolling an even number is the event 6.

Probability of an Event

The measure of the likelihood of the event occurring.

Example: P(rolling an even number) = 3/6 = 1/2.

Complementary Events

Events A and A' are complementary if P(A) + P(A') = 1.

Example: P(not rolling a 6) = 1 - P(rolling a 6) = 1 - 1/6 = 5/6.