The effect of air pollution on neonatal mortality.
Fifteen sets of identical twins were enrolled in a study to measure the effect of air pollution on neonatal mortality. One twin in each set was randomly assigned to the intervention group (renewable energy) or control group (non-renewable energy). At the end of the day, the Air Quality Index (AQI) was recorded, as shown in the data below.
| Subject id | AQI 1 | AQI 2 |
| 1 | 65 | 83 |
| 2 | 67 | 75 |
| 3 | 75 | 72 |
| 4 | 77 | 76 |
| 5 | 69 | 78 |
| 6 | 65 | 80 |
| 7 | 73 | 72 |
| 8 | 78 | 81 |
| 9 | 70 | 70 |
| 10 | 72 | 78 |
| 11 | 73 | 77 |
| 12 | 79 | 71 |
| 13 | 68 | 87 |
| 14 | 73 | 70 |
| 15 | 71 | 75 |
