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 .34.
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)?
( , )
The above questions requires us to find the sample size and confidence interval. Below is the approach to each; n=z-score 2... View the full answer
Sign up to view the full answer
a) Note that the sample size is given by n=p(1-p)(z*/E) 2 where E =margin of error=0.02 Now we are given that p=0.34 Also at... View the full answer