Sample Characteristics: Means (SE) and Weighted Frequencies by Race/ethnic Subgroups, National Longitudinal Study of Adolescent Health.a.

Abbreviations: SE, standard error; BMI, body mass index; HS, high school.**********aWeighted for national representation, standard errors corrected for survey design effects of multiple stage cluster sampling.bScreen time = hours of TV, video, and computer game use per week; estimates averaged across waves (wave II–IV).cPhysical activity = weekly bouts of moderate to vigorous physical activity; estimates averaged across waves (wave II–IV).dCurrent smoking: any cigarette smoking in previous 30 days; adolescence: age = 18.