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 1 of 3

Observational or experiment?

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Classify each study.

A retailer randomly shows half of its website visitors a new checkout page and compares purchase rates.
A health authority compares heart-disease rates of people who report eating fish weekly with those who do not.
A ministry compares unemployment in regions that introduced a job-training scheme with regions that did not.
An agronomist assigns fertiliser types to 36 field plots using a random number table and measures the wheat yield.
A gym chain analyses whether members who use its app attend more classes.
A call centre randomly assigns new agents to one of two training programmes and compares their call-resolution rates after a month.