# Probability rules

> A possible result of a random process.

Course: [Practical statistics and inference](https://studybrix.com/en/courses/statistics-foundations/index.md)
Level: university
Prerequisites: High-school algebra.

## Notes

### Outcome

A possible result of a random process.

### Event

A set of one or more outcomes.

### Conditional probability

The probability of an event given stated information about another event.

### Independence

A relationship where knowing one event occurred does not change the probability of the other.

## Practice questions

### 1. Which term best matches this description: A possible result of a random process.

A. Independence
B. Outcome
C. Conditional probability
D. Event

Answer: Outcome

Explanation: Outcome is the matching concept in this lesson.

### 2. Which term best matches this description: A set of one or more outcomes.

A. Independence
B. Event
C. Outcome
D. Conditional probability

Answer: Event

Explanation: Event is the matching concept in this lesson.

### 3. Which concept would you apply first in a situation where the probability of an event given stated information about another event.

A. Conditional probability
B. Event
C. Outcome
D. Independence

Answer: Conditional probability

Explanation: The scenario directly calls for Conditional probability.

### 4. Name the concept described as: A relationship where knowing one event occurred does not change the probability of the other.

Answer: Independence

Explanation: The intended concept is Independence.

### 5. Which statement about Outcome is most accurate?

A. A possible result of a random process.
B. A set of one or more outcomes.
C. A relationship where knowing one event occurred does not change the probability of the other.
D. The probability of an event given stated information about another event.

Answer: A possible result of a random process.

Explanation: The definition in the lesson notes gives the required condition.

### 6. Explain one important difference between Outcome and Event.

Sample answer / marking guidance: Outcome: A possible result of a random process. Event: A set of one or more outcomes.

Explanation: Credit a clear distinction using both definitions and an appropriate example if supplied.

### 7. Give a short example showing how Conditional probability would be used in practice.

Sample answer / marking guidance: A valid example should demonstrate this idea: The probability of an event given stated information about another event.

Explanation: Credit a relevant scenario that applies the concept rather than merely naming it.

### 8. Summarize why Independence matters in the lesson “Probability rules”.

Sample answer / marking guidance: Independence matters because A relationship where knowing one event occurred does not change the probability of the other.

Explanation: Credit the core purpose, scope and any important limitation from the notes.

## Further reading

- https://www.openintro.org/book/os/

Original AI-assisted educational draft; not independently teacher-reviewed. References support further study, not copied exercises, affiliation or curriculum accreditation.