How are confidence intervals calculated?

My client has requested 95% +- confidence intervals for numerical survey responses (sample question: How many employees did you have in 2006?). I have researched the topic online but have found no step by step instructions on how to deliver these. A step by step breakdown (for someone with almost no stats knowledge) of how I can achieve confidence intervals for totals would be greatly appreciated.


TS Contributor
I don't believe you are looking to compute a confidence interval for a total. What I assume you need to do is compute a confidence interval for the average of the totals reported, which is done in the usual way.