Statistical Charts and Digrams
9.4 Statistical Charts and Diagrams – Cheat Sheet
1. Bar Charts
- Represent data using rectangular bars.
- Bar length/height is proportional to the value or frequency.
- Bars are of equal width, with gaps between them.
- Used for discrete or categorical data.
Example:
| Item | Frequency |
|---|---|
| Apples | 8 |
| Bananas | 5 |
| Oranges | 7 |
2. Pie Charts
- Circular chart divided into sectors.
- Each sector’s angle is proportional to the frequency.
- Formula for sector angle:
Angle = (Frequency / Total) × 360° - Good for showing proportions.
Example:
If total = 40 and frequency for Apples = 8:
Angle = (8 / 40) × 360° = 72°
3. Pictograms
- Use symbols or pictures to represent data.
- Each symbol represents a fixed number of items.
- Symbols can be whole or part symbols for non-whole values.
Example:
If 🍎 = 4 apples, then 6 apples = 1½ symbols.
4. Simple Frequency Distributions
- Table that shows the number of observations for each category or value.
Example:
| Score | Frequency |
|---|---|
| 1 | 3 |
| 2 | 5 |
| 3 | 2 |
5. Composite (Stacked) Bar Charts
- Bars divided into sections to compare parts of a whole.
- Sections stacked vertically for each category.
Example:
A stacked bar could show different fruit types sold each day.
6. Dual (Side-by-Side) Bar Charts
- Two bars for each category placed side-by-side.
- Used to compare two related sets of data for the same category.