Mean number of cigarettes smoked in period between visits. The figure shows the changes in the mean number of cigarettes smoked each day at baseline, and then during the 6 days between each visit. These are shown for the group receiving placebo (placebo group), those receiving atomoxetine who completed the study (atomoxetine group), and those who received atomoxetine but dropped out during the study (last observation carried forward (LOCF) atomoxetine group). It can be seen that there was a marked drop in all groups. A two-sample t test demonstrated statistically significant difference (P < 0.05) between the atomoxetine group and placebo groups during this last measurement period (*).