Data Collection Examples in Statistics

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Data Collection.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Statistics.

Concept Recap

The systematic process of gathering information (data) to answer questions or learn about a topic.

Imagine you want to know your class's favorite ice cream flavor. You can't just guess - you need to actually ask everyone and write down their answers. That's data collection! It's like being a detective who gathers clues before solving a mystery.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Good data comes from systematic collection with clear questions — random or convenience collection leads to unreliable conclusions.

Common stuck point: Students confuse 'collecting more data' with 'collecting better data.' A large biased sample is still biased.

Worked Examples

Example 1

easy
A student wants to find out the favourite sport of students in her school. She decides to ask every student in her class. Is this a good method of data collection? Explain.

Solution

  1. 1
    Step 1: Identify the population of interest — all students in the school.
  2. 2
    Step 2: The student only surveys her own class, which is a subset. This may not represent the whole school because different classes may have different preferences.
  3. 3
    Step 3: A better method would be to survey students from multiple classes or use a random sample from the entire school.

Answer

No — surveying only one class introduces bias. A random sample from the whole school would be more representative.
Data collection methods must match the population we want to learn about. Using a convenience sample (one class) can produce biased results that do not generalise to the whole school.

Example 2

easy
Classify each data-collection method as a survey, an observation, or an experiment: (a) Recording how many cars pass a junction each hour. (b) Asking 50 people their favourite colour. (c) Giving one group of plants fertiliser and another group none, then measuring growth.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
A town council wants to know whether residents support building a new park. They place a survey form in the local library. Give one reason this method might produce biased results and suggest an improvement.

Example 2

easy
A school wants to know how many students ride the bus. They ask the first 20 students who enter through the front door on Monday morning. Identify one source of bias and suggest a better method.
← Back to Data Collection Practice Mode

Background Knowledge

These ideas may be useful before you work through the harder examples.

counting