A subsample of the 2011 MTF survey suggests that black adolescents don't perceive consuming four to five drinks per day as risky as do white adolescents. Of the 179 black adolescents who answered the question about alcohol consumption, 11.2% reported that consuming four to five drinks per day is "no risk." However, of the 783 white adolescents who answered the same question, only 4.7% reported that consuming four to five drinks per day is "no risk."
a. Calculate the 95% confidence interval for each proportion reported.