Random samples and bias

Compare simple random, systematic, stratified, convenience and self-selected samples, and identify the ways a sample can become biased.

⏱ 20 min❓ 9 questions

What you'll be able to do

✔I can tell random sampling methods from non-random ones
✔I can work out a systematic or stratified sample
✔I can identify sources of bias in the way a sample is chosen or questioned

How this works

1Read the short explanations first — they teach you what you need before each question.
2Answer each question, then tap Check. A right answer moves you on automatically; if it's wrong, you'll see a friendly explanation of why.
3Finish all 3 steps to see your score — sign in and subscribe to unlock the full lesson and save it.

What's inside

9 questions and 1 quick teaching card, including:

🔗Match the pairs — Choose the partner that goes with each item.
🔘Multiple choice — Tap the answer you think is best, then check it.

👪Grown-up tip: sit alongside younger learners for the first few lessons. Read the questions together and chat about the explanations — that's where the real learning sticks.

Curriculum: AC9M8ST02