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Was there an interaction between nicotine and menthol at that that level particularly? Otherwise, does it indicate that the 5.2 mg/g group did not follow the trend due to some kind of bias? If the interaction occurred at a particular concentration, does it mean that changing concentration of menthol may increase or decrease the number of cigarettes smoked according to concentration of nicotine in the cigarette? If menthol is known to reduce nicotine metabolism in body, how can this outlier be explained?