Student 1 used the same method four times to measure the time taken for a colour change during a reaction.
| Repeat | Time / s\text{s}s |
|---|---|
| 1 | 42.1 |
| 2 | 41.9 |
| 3 | 49.6 |
| 4 | 42.0 |
Student 2 used the same method. Student 2's results are summarised in the table.
| Student | Mean reaction time / s\text{s}s | Range / s\text{s}s |
|---|---|---|
| 2 | 41.5 | 1.4 |
Give the anomalous result.
Calculate the mean reaction time and its estimated uncertainty.
Give your answer in the form mean ± \pm\,± uncertainty.
Compare Student 1's results with Student 2's results.
Which student's mean can be trusted more? Give a reason.
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.