Calculating 95% Confidence Intervals for Prevalence (%)

Hi All,

I am hoping to get some advice on how I can calculate the 95% Confidence Intervals for prevalence percentages. My sample size is 180, and I am currently using the statistical package SPSS.

If anyone has any suggestions they would be appreciated!

Thanks so much for the reply. Will give that a go!

Does any one know if there is a way to calculate 85% CIs for percentages using SPSS?

I used np>10 and n(1-p)>10 as my assumptions. If this is violated I have used the Wilson estimate method (also known as the plus four estimate). Hope that's the correct way of doing it so please let me know if it's not!