Data Collection
Year 7 📈 Statistics & Probability Types of data, tally charts, frequency tables and surveys.
📋 Types of Data
Data can be qualitative (categories) or quantitative (numerical). Quantitative data is either discrete (countable) or continuous (measurable).
| Type | Examples |
|---|---|
| Qualitative | Favourite colour, nationality |
| Discrete | Number of siblings, shoe size |
| Continuous | Height, weight, temperature |
📊 Frequency Tables and Tally Charts
Frequency tables organise raw data into a clear summary, often using tally marks for counting.
Example: 20 students chose their favourite subject. Tally: Maths ||||| |||| (9), Science ||||| ||| (8), English ||| (3). The frequency column shows these totals, and they should add up to 20.
Group tally marks in fives (four upright strokes and a diagonal cross-stroke) to make counting easier.
🔍 Questionnaires and Sampling
Good data collection requires careful question design and a representative sample.
- Random sample: Every member of the population has an equal chance of being chosen.
- Biased sample: Only certain members are included, making results unreliable.
Avoid leading questions such as "Don't you agree that maths is the best subject?" Keep questions neutral, specific, and easy to answer.
Ready to test yourself? Click the Quiz tab above to answer questions on this topic!
Interactive Demonstration — Data Collection
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Interactive demonstration available in the Calculator tab!
📋 Data Collection Helper
Enter comma-separated data values to generate a frequency table.