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Significance testing

Statistical comparisons between groups/years were tested using regression analysis, with p<0.05 as the cut-off for significance. Bootstrap weights were used to perform significance testing between groups or between the latest two years, where they were available (Canadian Tobacco, Alcohol and Drugs Survey (CTADS) 2013, Canadian Tobacco Use Monitoring Survey (CTUMS)  2001 to 2012, and Youth Smoking Survey (YSS) 2004-05 to 2012-13). The statistical comparisons were performed using the SURVEYLOGISTIC procedure in the Statistical Analysis System (SAS; Version 9.4) for all binary response variables. For the continuous variable of cigarettes per day, comparisons were performed using the SURVEYREG procedure in SAS. Comparisons of prevalence rate and cigarettes per day (CPD) over the time period 1999-2013 (#4, #5, #13 and #14) were tested using a dataset of the prevalence rates and CPD by year. The GLM procedure in SAS was used with the yearly prevalence rate regressed on year for #4, the log of yearly prevalence rate regressed on year for #5, yearly CPD regressed on year for #13 and log of yearly CPD regressed on year for #14.

Where statistical testing has been performed, comparisons are marked with a superscript number, which refers to a p-value that can be found in the Index of Statistical Tests. Throughout the report, the term “significant” has been reserved for instances where statistical testing has been performed at the five per cent of level of significance (i.e., p<0.05).