sample although they constituted 3% of the study area population. In order to generalize results back to the target population, observations were weighted proportionately to the inverse of their selection probability. Participation included 1420 individuals (56% male); 508 aged 9, 497 aged 11, and 415 aged 13. This was 80% of the target sample. Consistent with the population make-up, approximately 8% was African American and less than 1% was Hispanic.
