Correlation coefficients for key variables (95% confidence intervals) (upper diagonal = United Kingdom; lower diagonal = all combined)
| Standard tar (mg) | Standard nicotine (mg) | Standard CO (mg) | Percent ventilation | Total nicotine | Percent nicotine | Filter weight | |
|---|---|---|---|---|---|---|---|
| Standard tar | 1.00 | 0.96 (0.92 to 0.98) | 0.97 (0.93 to 0.98) | -0.86 (-0.93 to −0.74) | 0.03 (-0.29 to 0.35) | -0.49 (-0.70 to −0.20) | −0.45 (−0.68 to −0.15) |
| Standard nicotine | 0.94 (0.91 to 0.96) | 1.00 | 0.91 (0.84 to 0.96) | −0.85 (−0.92 to −0.73) | 0.09 (−0.24 to 0.40) | −0.40 (−0.64 to −0.08) | −0.51 (−0.71 to −0.22) |
| Standard CO | 0.97 (0.95 to 0.98) | 0.89 (0.83 to 0.93) | 1.00 | −0.92 (−0.96 to −0.84) | −0.00 (−0.33 to 0.32) | −0.50 (−0.71 to −0.20) | −0.35 (−0.61 to −0.03) |
| Percent ventilation | −0.86 (−0.91 to −0.80) | −0.78 (−0.85 to −0.68) | −0.92 (−0.95 to −0.88) | 1.00 | 0.05 (−0.28 to 0.36) | 0.42 (0.11 to 0.65) | 0.37 (0.05 to 0.62) |
| Total nicotine | 0.16 (−0.04 to 0.36) | 0.33 (0.13 to 0.50) | 0.10 (−0.11 to 0.30) | −0.04 (−0.24 to 0.17) | 1.00 | 0.73 (0.53 to 0.85) | 0.25 (−0.08 to 0.53) |
| Percent nicotine | −0.20 (−0.39 to 0.001) | −0.04 (−0.24 to 0.17) | −0.27 (−0.45 to −0.06) | 0.26 (0.06 to 0.44) | 0.82 (0.75 to 0.88) | 1.0 | 0.37 (0.05 to 0.62) |
| Filter weight | −0.54 (−0.67 to −0.37) | −0.63 (−0.74 to −0.49) | −0.43 (−0.59 to −0.25) | 0.35 (0.15 to 0.51) | −0.32 (−0.49 to −0.12) | −0.05 (−0.25 to 0.16) | 1.0 |