Demographic characteristics
SD
Grade 7 and 8 students from two junior middle schools in Changzhou (n = 724) completed the entire study were randomly divided into a course group (n = 359) and a control group (n = 365). There was no statistical difference between the course group and the control group in terms of age, gender, grade, ethnicity, previous academic performance, family type, and parental education level. The two groups of students are balanced in demography characteristics (
Baseline demographic characteristics of students stratified by the course and control groupNote: Age and other normally distributed measurement data were described by Mean ± SD and compared using 