Two students measured the time taken for the same type of reaction mixture to change colour. Each student repeated the measurement five times using the same method.
| Repeat | Student A time in s | Student B time in s |
|---|---|---|
| 1 | 52.1 | 51.8 |
| 2 | 52.3 | 52.6 |
| 3 | 52.2 | 52.1 |
| 4 | 55.9 | 52.4 |
| 5 | 52.2 | 52.0 |
Calculate the mean time and estimated uncertainty for Student A's results.
Give your answer in the form mean ± uncertainty.
Explain which student's mean is more trustworthy.
95 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.