• Quick retrieval from earlier learning (Spotting misleading statistics and graphs; Which finding would weaken (or strengthen) a claim?). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Is the proposed answer correct? "Since the new road opened, house prices have risen 10%." Why can't we say the road caused it? → prices may have risen everywhere for other reasons (yes, it is correct / no, it is not correct) → yes, it is correctPrompt: Ask: how many people or cases is this based on, and who was asked?
2. Is the proposed answer correct? A researcher claims that a new fertiliser causes tomato plants to produce more fruit. Which finding would most directly WEAKEN this claim? → Tomatoes are popular in many countries. (yes, it is correct / no, it is not correct) → no, it is not correctPrompt: Restate the claim exactly. What would have to be true if it were right?
3. Read the question and choose. "Since the new road opened, house prices have risen 10%." Why can't we say the road caused it? (roads never affect prices / house prices can't rise / prices may have risen everywhere for other reasons / 10% is a small number) → prices may have risen everywhere for other reasonsPrompt: Ask: how many people or cases is this based on, and who was asked?

• Read the first lines of a short text aloud and ask what students predict will happen and why.
• Share the objective: Does the study design support the claim?. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: A study tracked 50,000 adults for ten years and found that those who walked daily had fewer heart problems. The researchers adjusted for age, smoking and diet, and said walking 'may help protect' the heart. Why is the researchers' wording appropriate?
• Step 1: Strong evidence for a cause comes from fair comparisons (ideally randomised, with control groups) on large, representative samples; claims should match the strength of the evidence.
• Step 2: Observational data, however large, justify cautious language.
• Step 3: So the answer is: Even a large, careful observational study can suggest but not prove cause, so 'may help' is suitably cautious.
• Answer: Even a large, careful observational study can suggest but not prove cause, so 'may help' is suitably cautious.
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Is the proposed answer correct? A study tracked 50,000 adults for ten years and found that those who walked daily had fewer heart problems. The researchers adjusted for age, smoking and diet, and said walking 'may help protect' the heart. Why is the researchers' wording appropriate? → Even a large, careful observational study can suggest but not prove cause, so 'may help' is suitably cautious. (yes, it is correct / no, it is not correct) → yes, it is correctPrompt: Ask: Was there a fair comparison group? How big and representative was the sample?
2. A study tracked 50,000 adults for ten years and found that those who walked daily had fewer heart problems. The researchers adjusted for age, smoking and diet, and said walking 'may help protect' the heart. Why is the researchers' wording appropriate? (The study was too small to say anything. / Ten years is too short to study health. / They should have said walking definitely cures heart disease. / Even a large, careful observational study can suggest but not prove cause, so 'may help' is suitably cautious.) → Even a large, careful observational study can suggest but not prove cause, so 'may help' is suitably cautious.Prompt: Ask: Was there a fair comparison group? How big and representative was the sample?

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. A company asked 15 of its own employees whether its new chair reduced back pain. Twelve said yes. The company now advertises that "80% of users report less back pain". What is the biggest problem with this evidence? (Chairs can't be tested. / The sample is tiny and made up of people who may want the product to succeed. / 80% is not a real percentage. / Back pain is not a real problem.) → The sample is tiny and made up of people who may want the product to succeed.Prompt: Ask: Was there a fair comparison group? How big and representative was the sample?
2. Is the proposed answer correct? To test a new memory app, researchers randomly assigned 200 students either to use the app or to use a version with the memory games removed. After a month, the app group recalled more words. Why is this design fairly strong evidence that the app helps? → Random assignment and a comparison group make other explanations less likely. (yes, it is correct / no, it is not correct) → yes, it is correctPrompt: Ask: Was there a fair comparison group? How big and representative was the sample?

Free online practice with hints and printable worksheets for this skill: eurekami.com/english/grade-11.