An environmental scientist carried out a study to investigate whether daily average PM2.5\text{PM}_{2.5}PM2.5 concentration is associated with respiratory health in an urban area.
| Day | Daily average PM2.5\text{PM}_{2.5}PM2.5 concentration (μg/m3\mu\text{g/m}^3μg/m3) | Respiratory discomfort index (10–100) | Ranks of the data collected | |
|---|---|---|---|---|
| Daily average PM2.5\text{PM}_{2.5}PM2.5 concentration (μg/m3\mu\text{g/m}^3μg/m3) | Respiratory discomfort index (10–100) | |||
| A | 8 | 24 | 1 | 1 |
| B | 18 | 40 | 4 | 4 |
| C | 12 | 30 | 3 | 3 |
| D | 22 | 54 | 6 | 6 |
| E | 28 | 62 | 8 | 8 |
| F | 45 | 86 | 12 | 12 |
| G | 20 | 46 | 5 | 5 |
| H | 32 | 70 | 9 | 9 |
| I | 25 | 56 | 7 | 7 |
| J | 10 | 28 | 2 | 2 |
| K | 40 | 80 | 11 | 11 |
| L | 38 | 78 | 10 | 10 |
Calculate the mean respiratory discomfort index from this dataset. Show your workings and present your finding to 2 significant figures.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.