Beta weights (95% confidence intervals) for multiple regression equations predicting standard tar and nicotine yields of Canadian cigarettes from percent ventilation, percent nicotine in tobacco, nicotine content per cigarette, and filter weight. Each column describes a different regression equation.
| Predicting tar yields | Predicting nicotine yields | |||||||
|---|---|---|---|---|---|---|---|---|
| Percent ventilation | −0.90 (−1.11 to −0.69) | −0.90 (−1.11 to −0.69) | −0.71 (−0.94 to −0.48) | −0.67 (−0.86 to −0.48) | −0.86 (−1.13 to −0.59) | −0.85 (−1.10 to −0.60) | −0.66 (−0.95 to −0.37) | −0.60 (−0.87 to −0.33) |
| Percent nicotine (mg nicotine/mg tobacco) | −0.01 (−0.18 to 0.16) | NA | −0.84 (−1.48 to −0.20) | −0.72 (−1.26 to −0.18) | 0.07 (−0.20 to 0.34) | NA | −0.81 (−1.63 to 0.01) | −0.67 (−1.39 to 0.05) |
| Total nicotine (nicotine/cigarette) (mg)) | NA | 0.05 (−0.14 to 0.24) | 0.83 (0.19 to 1.47) | 0.84 (0.32 to 1.36) | NA | 0.13 (−0.12 to 0.38) | 0.88 (0.09 to 1.67) | 0.90 (0.22 to 1.58) |
| Filter weight (mg) | NA | NA | NA | −0.27 (−0.44 to −0.10) | NA | NA | NA | −0.34 (−0.57 to −0.11) |
| Intercept | 17.1 | 15.5 | 18.7 | 39.7 | 1.37 | 1.24 | 1.51 | 3.8 |
| RMS error | 1.98 | 1.96 | 1.72 | 1.39 | 0.22 | 0.21 | 0.20 | 0.17 |
| R 2 (all p<0.0001) | 0.81 | 0.82 | 0.87 | 0.92 | 0.71 | 0.72 | 0.77 | 0.84 |
NA = not applicable.