Predictive value of regression model for each age category, with variance explained (R2), goodness of fit, and correctly classified smokers
| Age (years) | R2 | Goodness of fit | Correctly classified smokers (%) | Smokers (%) | n |
|---|---|---|---|---|---|
| 11 | 19.8 | 612 | 66.67 | 8.2 | 608 |
| 13 | 31.3 | 500 | 73.75 | 15.5 | 554 |
| 15 | 40.6 | 662 | 79.49 | 24.7 | 651 |
| 17 | 53.0 | 143 | 80.00 | 38.7 | 150 |
R 2 was measured by Nagelkerke statistics.