Confidence intervals aren't difficult. Since you have a proportion, Just use the formula . This is the margin of error.And, confidence intervals are very hard. Can someone break how to do a 95% interval down. Say 1000 people were interviewed about smoking and 600 said they did. How would you do that interval? Can do you do it on a calculator?

p=0.60, q=1-p, n=1000. z that corresponds to 95% CI is 1.96

0.60+0.0304=0.6304; 0.60-0.0304=0.5696

So, you can say with 95% confidence that the proportion of people who say they smoke is between56.96% and 63.04%.