# Sampling and bias

> The full group a study aims to describe.

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

## Notes

### Population

The full group a study aims to describe.

### Sample

The observed subset used to learn about a population.

### Sampling bias

Systematic distortion caused by how observations are selected.

### Random sample

A probability-based selection design that gives defined selection chances.

## Practice questions

### 1. Which term best matches this description: The full group a study aims to describe.

A. Sample
B. Sampling bias
C. Population
D. Random sample

Answer: Population

Explanation: Population is the matching concept in this lesson.

### 2. Which term best matches this description: The observed subset used to learn about a population.

A. Random sample
B. Population
C. Sampling bias
D. Sample

Answer: Sample

Explanation: Sample is the matching concept in this lesson.

### 3. Which concept would you apply first in a situation where systematic distortion caused by how observations are selected.

A. Population
B. Random sample
C. Sample
D. Sampling bias

Answer: Sampling bias

Explanation: The scenario directly calls for Sampling bias.

### 4. Name the concept described as: A probability-based selection design that gives defined selection chances.

Answer: Random sample

Explanation: The intended concept is Random sample.

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

A. The full group a study aims to describe.
B. A probability-based selection design that gives defined selection chances.
C. Systematic distortion caused by how observations are selected.
D. The observed subset used to learn about a population.

Answer: The full group a study aims to describe.

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

### 6. Explain one important difference between Population and Sample.

Sample answer / marking guidance: Population: The full group a study aims to describe. Sample: The observed subset used to learn about a population.

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

### 7. Give a short example showing how Sampling bias would be used in practice.

Sample answer / marking guidance: A valid example should demonstrate this idea: Systematic distortion caused by how observations are selected.

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

### 8. Summarize why Random sample matters in the lesson “Sampling and bias”.

Sample answer / marking guidance: Random sample matters because A probability-based selection design that gives defined selection chances.

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.