Table 2

Descriptive statistics of outcome measures across experimental groups

Outcome variableE-cigarette adverts
(n=521)
Control adverts
(n=536)
Test statisticP values
Perceived harm of occasional tobacco smoking508.69546.84−2.1290.033
Perceived harm of tobacco smoking in general525.10529.84−0.4350.664
Perceived harm of regular tobacco smoking531.91524.18−0.5120.609
Perceived disease risk (regular smoking)529.87522.22−0.4150.678
Perceived disease risk (occasional smoking)540.36512.05−1.5240.127
Tobacco smoking prevalence estimates521.96513.12−0.4770.634
Susceptibility to tobacco smoking42.437.92.5150.113
Perceived harm of occasional e-cigarette use527.49530.47−0.1670.867
Perceived harm of e-cigarette use in general516.81539.84−1.2820.200
Perceived harm of regular e-cigarette use530.06527.97−0.1160.908
Perceived disease risk (regular e-cigarette use)520.34527.56−0.3890.697
Perceived disease risk (occasional e-cigarette use)523.22526.74−0.1930.847
E-cigarette use prevalence estimates523.19513.90−0.5010.616
Susceptibility to e-cigarette use50.149.80.0150.902
Appeal of adverts426.32628.80−10.797<0.001
Interest in buying and trying advertised product393.83660.39−14.298<0.001
  • For all outcome variables, the test statistic corresponds to the Z value from the Mann-Whitney U analyses (with corresponding mean ranks shown for each experimental group), except for the variables susceptibility to smoking and e-cigarettes use which are binary variables and are denoted by percentages summarised using the X 2 test statistic.