Table of Contents

- 1 How do you find the probability of an event occurring?
- 2 How do you find the probability of intersection?
- 3 How do you find the probability of union of three events?
- 4 What are the 3 ways of writing a probability?
- 5 When is the probability of getting 3 4s?
- 6 When do two events cannot happen at the same time?

## How do you find the probability of an event occurring?

The probability of an event is the number of favorable outcomes divided by the total number of outcomes.

**What is the probability that the event will occur?**

The probability of an event is a number describing the chance that the event will happen. An event that is certain to happen has a probability of 1. An event that cannot possibly happen has a probability of zero. If there is a chance that an event will happen, then its probability is between zero and 1.

### How do you find the probability of intersection?

We can find the probability of the intersection of two independent events as, P(A∩B) = P(A) × P(B), where, P(A) is the Probability of an event “A” and P(B) = Probability of an event “B” and P(A∩B) is Probability of both independent events “A” and “B” happening together.

**How do you find the probability of two events if event A is a subset of event B?**

The fourth basic rule of probability is known as the multiplication rule, and applies only to independent events: Rule 5: If two events A and B are independent, then the probability of both events is the product of the probabilities for each event: P(A and B) = P(A)P(B).

#### How do you find the probability of union of three events?

Union of three events (inclusion/exclusion formula): P(A ∪ B ∪ C) = P(A) + P(B) + P(C) − P(A ∩ B) − P(A ∩ C) − P(B ∩ C) + P(A ∩ B ∩ C).

**How do you find the intersection of three events?**

To calculate the probability of the intersection of more than two events, the conditional probabilities of all of the preceding events must be considered. In the case of three events, A, B, and C, the probability of the intersection P(A and B and C) = P(A)P(B|A)P(C|A and B).

## What are the 3 ways of writing a probability?

A probability can be written as a ratio, a fraction, and a percent.

**Is the probability of an event equal to 1?**

Since we know that either an event will occur or not, we know that the probability of the event occurring plus the probability of the event not occurring must equal to 1. More formally, we write: Let A be some event. Then, P (A) + P (A does not occur) = 1.

### When is the probability of getting 3 4s?

The probability of getting 3 4s is: When the outcome affects the second outcome, which is what we called dependent events. Dependent events: Two events are dependent when the outcome of the first event influences the outcome of the second event.

**How to calculate the probability of two dependent events?**

The probability of two dependent events is the product of the probability of X and the probability of Y AFTER X occurs. P (X a n d Y) = P (X) ⋅ P (Y a f t e r x)

#### When do two events cannot happen at the same time?

Two events are mutually exclusive when two events cannot happen at the same time. The probability that one of the mutually exclusive events occur is the sum of their individual probabilities.