Exam-style question
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A researcher wants to make an informal inference about a population from a sample. Which sampling method reduces selection bias? Show your working one step at a time.
Model answer
What a good answer should say
- The final answer is use a simple random sample.
- Identify the population as the full group being investigated.
- Identify the sample as the smaller group selected from the population.
- Use random selection so each member has a fair chance of being chosen.
This answer is tied to the objective: K1 Understand and use the terms population and sample; use samples to make informal inferences about the population; understand and use sampling techniques including simple random sampling and opportunity sampling; select or critique sampling techniques in context, including understanding that different samples can lead to different conclusions about the population..
Explanation
Why this works
Use the explanation to connect the worked answer back to K1 Understand and use the terms population and sample; use samples to make informal inferences about the population; understand and use sampling techniques including simple random sampling and opportunity sampling; select or critique sampling techniques in context, including understanding that different samples can lead to different conclusions about the population..
exam warm-up keeps the canonical answer use a simple random sample fixed before the model answer is written, so the worked solution and final answer agree.
Maths method check
- Topic focus: Statistics.
- Question style: exam_style.
- Reasoning demand: recall.
- Check the operation, notation, units, and final answer form against the question before moving on.
Common mistake
No common mistake is linked to this question yet.