A student made 20 repeat measurements of the same volume. Most of the results lay between 24.6 cm3 and 24.8 cm3, but one result was 26.0 cm3. What should the student do with the result of 26.0 cm3?
Include it, because every measurement must go into the mean.
Include it, because it shows the true spread of the results.
Exclude it, and then repeat all of the measurements again.
Exclude it as anomalous, and take the mean of the others.
40 exam-style questions on AQA GCSE Chemistry 3.1 Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations, covering 3.1.1 Conservation of mass and balanced chemical equations, 3.1.2 Relative formula mass, 3.1.3 Mass changes when a reactant or product is a gas, and 3.1.4 Chemical measurements. Each one has a worked solution and a mark scheme showing where the marks go.