The centers for disease control reported the percentage of people 18 years of age and older who smoke (cdc website, december 14, 2014). suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of .30.

a. how large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02 (to the nearest whole number)? use 95% confidence.
b. assume that the study uses your sample size recommendation in part (a) and finds 520 smokers. what is the point estimate of the proportion of smokers in the population (to 4 decimals)?
c. what is the 95% confidence interval for the proportion of smokers in the population (to 4 decimals)?