Moments of the distribution of the logarithm of the ratio N-3 demethylation metabolites of caffeine in nonsmokers and smokers
| Nonsmokers | Smokers | All | |
|---|---|---|---|
| Mean | 1.44 | 1.70 | 1.53 |
| Standard deviation | 0.28 | 0.36 | 0.33 |
| Kurtosis | 0.48 | −0.57 | 0.57 |
| Skewness | −0.59 | 0.26 | 0.13 |