The Youth Risk Behavior Surveillance System (YRBSS) monitors
The Youth Risk Behavior Surveillance System (YRBSS) monitors health risk behaviors among U.S. high school students, which include tobacco use, alcohol and drug use, inadequate physical activity, unhealthy diet and risky sexual behavior. Approximately 8% of youth have tried marijuana before reaching age 13 years. How does marijuana use change over the high school years? In 2011, the survey randomly selected 3681 ninth-graders and 3632 twelfth-graders and asked them if they had used marijuana one or more times during the previous 30 days. Of these students, 664 ninth-graders and 1010 twelfth-graders said yes. Give a 99% confidence interval for the difference between the proportions of all ninth and twelfth-grade high school students who smoked marijuana at least once in the 30 days prior to the survey.The 99% confidence interval (±0.0001) is from to