Lesson 2: Representative Sampling

About 30 minutes — Activity-based lesson

What You Will Learn

This lesson covers:

Random sampling: everyone has an equal chance of being selected
Stratified sampling: ensuring important subgroups are included
Why convenience sampling is tempting but dangerous
Activity: design 3 sampling strategies for the same research question

Random sampling: everyone has an equal chance of being selected

This section covers the key ideas about random sampling: everyone has an equal chance of being selected. Discuss with your group or family and explore the concepts together.

Stratified sampling: ensuring important subgroups are included

This section covers the key ideas about stratified sampling: ensuring important subgroups are included. Discuss with your group or family and explore the concepts together.

Why convenience sampling is tempting but dangerous

This section covers the key ideas about why convenience sampling is tempting but dangerous. Discuss with your group or family and explore the concepts together.

Activity: design 3 sampling strategies for the same research question

This section covers the key ideas about activity: design 3 sampling strategies for the same research question. Discuss with your group or family and explore the concepts together.

Check Your Understanding

1. What is random sampling?

Answer: A method where every member of the population has an equal chance of being selected. Like drawing names from a hat — it prevents systematic bias.

2. What is stratified sampling?

Answer: Dividing the population into important subgroups (like grades or genders) and randomly sampling from each group proportionally. This ensures all groups are represented.

3. What is convenience sampling?

Answer: Surveying whoever is easiest to reach — like only asking your friends or only people in one class. It is fast but often produces biased results.

4. Which sampling method is best?

Answer: Random sampling is usually best for avoiding bias. Stratified sampling adds precision when you know important subgroups exist. Convenience sampling should be used cautiously.

Key Takeaways

Random sampling: everyone has an equal chance of being selected
Stratified sampling: ensuring important subgroups are included
Why convenience sampling is tempting but dangerous
Activity: design 3 sampling strategies for the same research question

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