A survey in Australia found that 21% of all Americans aged 16 to 20 drove under the influence of drugs or alcohol. A similar survey is planned for New Zealand. How large a sample is required if they want a 95% confidence interval to be accurate within 3.5%?
Additional Information
This question is based on Statistics and it is about estimating the percentage of youngsters between 16-0 driving under drugs or alcohol. The test is to be conducted in New Zealand and the sample size is to be estimated.