a researcher wishes to estimate the proportion of people within a certain population who are in favor of a national health care system obtain a sample size that will ensure a marding of error of at most 0.01 for a 95% confidence Solution Given E=0.01, a=0.05, |Z(0.025)|=1.96 (check standard normal table) So n=(Z/E)^2*p*(1-p) =(1.96/0.01)^2*0.5*0.5 =9604.