**Introduction**

Probability is the measurement of how likely an event is to happen. It quantifies the level of uncertainty related to outcomes and is represented as a value between 0 and 1. A probability of 0 indicates impossibility, while a probability of 1 suggests certainty.

**1- Sample Space:**The sample space refers to all the possible outcomes of a random experiment.**2- Event:**An event is a specific outcome or a group of outcomes within the sample space.**3- Probability of an Event:**The probability of an event is a number between 0 and 1 that indicates the chance of that event happening. A probability of 0 means the event is impossible, while a probability of 1 means it is certain.**4- Equally Likely Outcomes:**If all outcomes in the sample space are equally likely, the probability of an event A can be calculated by dividing the number of favorable outcomes for A by the total number of outcomes.**5- Probability Distribution:**A probability distribution assigns probabilities to each possible outcome in a sample space, indicating the likelihood of occurrence.**6- Independent Events:**Two events A and B are independent if the probability of one event occurring does not affect the probability of the other event occurring. The probability of both independent events A and B happening is the product of their individual probabilities.**7- Mutually Exclusive Events:**Two events A and B are mutually exclusive if they cannot happen simultaneously. If A and B are mutually exclusive, the probability of either A or B occurring is the sum of their individual probabilities.**8- Conditional Probability:**Conditional probability measures the probability of event A occurring, given that event B has already occurred. It is denoted as P(A|B) and is calculated by dividing the probability of both A and B occurring by the probability of event B.**9- Complementary Event:**The complementary event of an event A, denoted as A', is the event that A does not occur. The probability of the complementary event A' is equal to 1 minus the probability of A.