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

Random or systematic error?

Not started

Classify each source of measurement error.

A stopwatch operator sometimes presses a little early and sometimes a little late.
A thermometer in a server room is mounted next to an air vent and always reads 2 °C cooler than the room.
Survey respondents under-report how much fast food they eat.
Small fluctuations in a laboratory balance's readings caused by air currents.
A sales system records all transactions in the time zone of head office, so evening sales in another region appear on the next day.