A previous survey of Washington residents showed that 18% of residents accessed a state park within the last 12 months. This year, the state would like to re-administer the survey, but wants to be sure the Margin of Error in their new study will be at most 4%. Assuming they believe the previous survey's results were reliable, how many samples should they take to ensure their Margin of Error is at most 4% if they plan to analyze the data using a 95% confidence interval