# Visualization and summaries

> How observed values are spread across possible outcomes.

Course: [Data science foundations](https://studybrix.com/en/courses/data-science/index.md)
Level: university
Prerequisites: Algebra and basic statistics.

## Notes

### Distribution

How observed values are spread across possible outcomes.

### Median

The middle ordered value, or midpoint of the two middle values.

### Histogram

A graph grouping numerical observations into intervals.

### Encoding

A visual mapping from data values to position, size, colour or another mark property.

## Practice questions

### 1. Which term best matches this description: How observed values are spread across possible outcomes.

A. Encoding
B. Distribution
C. Histogram
D. Median

Answer: Distribution

Explanation: Distribution is the matching concept in this lesson.

### 2. Which term best matches this description: The middle ordered value, or midpoint of the two middle values.

A. Median
B. Distribution
C. Encoding
D. Histogram

Answer: Median

Explanation: Median is the matching concept in this lesson.

### 3. Which concept would you apply first in a situation where a graph grouping numerical observations into intervals.

A. Distribution
B. Median
C. Encoding
D. Histogram

Answer: Histogram

Explanation: The scenario directly calls for Histogram.

### 4. Name the concept described as: A visual mapping from data values to position, size, colour or another mark property.

Answer: Encoding

Explanation: The intended concept is Encoding.

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

A. How observed values are spread across possible outcomes.
B. A visual mapping from data values to position, size, colour or another mark property.
C. The middle ordered value, or midpoint of the two middle values.
D. A graph grouping numerical observations into intervals.

Answer: How observed values are spread across possible outcomes.

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

### 6. Explain one important difference between Distribution and Median.

Sample answer / marking guidance: Distribution: How observed values are spread across possible outcomes. Median: The middle ordered value, or midpoint of the two middle values.

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

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

Sample answer / marking guidance: A valid example should demonstrate this idea: A graph grouping numerical observations into intervals.

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

### 8. Summarize why Encoding matters in the lesson “Visualization and summaries”.

Sample answer / marking guidance: Encoding matters because A visual mapping from data values to position, size, colour or another mark property.

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

## Further reading

- https://pandas.pydata.org/docs/
- 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.