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Table 5 Information for estimating PPV for those scoring 9 or more in the 2001 population survey

From: Development of a questionnaire weighted scoring system to target diagnostic examinations for asthma in adults: a modelling study

Stratum (i) (number of 'yes' answers to key questions)

Score (j)

Number of respondents

ω ij proportion of population postal questionnaires in stratum i,

∏' ij prevalence of asthma for score j in stratum i

ω ij × ∏' 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

  
  1. Estimated PPV for those scoring 9 or more: