Read the News Story Below $\quad$ $\quad$

Essay

Read the news story below. Using the 95 percent confidence level, what sample size would be needed to estimate the true proportion of stores selling cigarettes to minors with an error of ± 3 percent? Explain carefully, showing all steps in your reasoning.
$\quad$$\quad$$\quad$ Decoys Catch Stores in Cigarette-Sale Sting
The Tri-Cities Tobacco Reduction coalition recently sent three underage teenagers out to see whether they could buy cigarettes from stores in Detroit and Highland Park. The results were not good.
Of the 320 stores checked, 82 sold cigarettes to the teens, who were between the ages of 15 and 17. People must be 18 to legally buy cigarettes in Michigan. When the age of the buyer is not clear, the retailer is supposed to check the buyer's ID. The stores that sold the cigarettes will face fines.
Source: Detroit Free Press, March 19, 2001, p. 2C.