Definition of Probability

Probability is the measure of how likely an event is to occur. Understanding how to calculate probabilities and the relationships between different events is fundamental in statistics.

Basic Probability Concepts

Probability of an Event (P(E))

The probability of an event $E$ is calculated as:

$$P(E) = \frac{\text{Number of favourable outcomes}}{\text{Total number of possible outcomes}}$$

Complementary Events

The complement of an event $E$ is the event that $E$ does not occur.

If $P(E)$ is the probability of $E$ , then the probability of the complement $E'$ is:

$$P(E') = 1 - P(E)$$