Statistics Quest

Practice

Practise until it sticks

Choose a topic, a skill or a difficulty. Calculation exercises have new versions with fresh numbers once you have solved them, so you can practise the method rather than memorise an answer.

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Practice, difficulty 2 of 3

Is a causal claim justified?

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For each study, decide whether the causal claim is justified by the design, or whether only an association has been shown.

Users randomly shown a shorter sign-up form completed sign-up more often. Claim: the shorter form increases completion.
Neighbourhoods with more parks have fewer hospital admissions. Claim: parks reduce admissions.
Patients randomly assigned to a new physiotherapy programme regained mobility faster than those on standard care. Claim: the programme speeds recovery.
Employees who take more training courses get promoted sooner. Claim: training causes promotion.
Countries with higher chocolate consumption have more prize-winning scientists. Claim: chocolate improves scientific ability.