Sample size calculation and data analysis
SECONDARY, BLIND
The primary trial outcome in the intent-to-treat (ITT) sample analysis was the between-group proportional difference in smoking abstinence (7-day point-prevalence abstinence and proportion of days abstinent). To guide our original decision on the size of the sample for the trial, we conducted an a priori power analysis using G*Power software (Heinrich-Heine-Universität Düsseldorf, Germany) (Participant data were input and stored in the secured Research Electronic Data Capture system. Upon the trial's completion, the data were shared with a third-party statistician consultant from the same university. The purpose was to blind key study personnel and the investigators to the knowledge of group assignment during all analyses until the primary outcome tests were completed by an impartial statistician. Group contrast effects on the primary and secondary outcomes of the trial were carried out using the ITT analytic approach (