Hints: First notice that the study involves a "Yes or No" question. You are interested in finding a confidence interval for a proportion here. In your calculator go to STAT then TESTS. Then scroll down until you find 1-PropZInt. x represents the number of successes and n represents the sample size. Here's how to interpret the confidence level. If many randomly selected groups, each with the given sample size are studied, then the results from each group would correspond to a separate confidence interval. The confidence level tells us what percent of these confidence intervals will contain the true population proportion