a: Hazard rates of initiating marijuana use for females ages 8-17 by ethnicity and region. These functions show the probability that a respondent would initiate marijuana use at age j, given that he or she had not been intoxicated before age j.
b: Hazard rates of initiating marijuana use for males ages 8-17 by ethnicity and region
Notes: W=White; AI=American Indian; NP=Northern Plains; SW=Southwest; UGL=Upper Great Lakes. Non-signficant coefficients for UGL and male*UGL were not used to calculate the hazard rates in Figures 2a and 2b.