The association of individual and school factors with male BMI in the Healthy Passages cohort.

` Ref = Reference group; sigma_u is the standard deviation of the school-level random effect; sigma_e is the standard deviation of the individual-level random effect.
aHigh school levels categorized into some high school, high school graduate or received GED, some college, and college graduate or beyond.
bSchool nutrition/physical activity index is a count of the positive nutrition and physical activity resources/programs reported in the school.