Methods: Students of the junior high, senior high, and vocational high schools in Taipei City and County were selected by a stratified, two-stage, probability proportional to size, random sampling.

• 方法：针对台北县市的国中、高中及高职的学生，进行分层暨二阶段之随机抽样，并配合让每个抽样单位被抽取到的机率与单位大小成比例。