Table 5.
Information for estimating PPV for those scoring 9 or more in the 2001 population survey
| Stratum (i) (number of 'yes' answers to key questions) | Score (j) | Number of respondents | ωij proportion of population postal questionnaires in stratum i, | ∏'ij prevalence of asthma for score j in stratum i | ωij × ∏'ij |
| 6 | 12 | 2 | 0.0250 | 0.9914 | 0.0248 |
| 6 | 11 | 6 | 0.0750 | 0.9914 | 0.0744 |
| 6 | 10 | 5 | 0.0625 | 0.9867 | 0.0616 |
| 6 | 9 | 7 | 0.0875 | 0.7996 | 0.0700 |
| 5 | 12 | 1 | 0.0125 | 0.7181 | 0.0090 |
| 5 | 11 | 3 | 0.0375 | 0.7181 | 0.0269 |
| 5 | 10 | 9 | 0.1125 | 0.9777 | 0.1100 |
| 5 | 9 | 16 | 0.2000 | 0.8938 | 0.1788 |
| 4 | 10 | 3 | 0.0375 | 0.8908 | 0.0334 |
| 4 | 9 | 11 | 0.1375 | 0.9975 | 0.1371 |
| 1 – 3 | 11 | 1 | 0.0125 | 0.9633 | 0.0120 |
| 1 – 3 | 10 | 3 | 0.0375 | 0.9757 | 0.0366 |
| 1 – 3 | 9 | 13 | 0.1625 | 0.9880 | 0.1606 |
| Total | 80 | 1 |
Estimated PPV for those scoring 9 or more:
