Calculating confidence level intervals.

[PCSL]

Any resources you can recommend? Preferably online but I'm not against stopping by the library if need be. Thank you.

 

[Simon Bridge]

It is commendable that you want ot learn this for yourself, however, there are many resources and without knowing your difficulties or context it is not possible to make a good suggestion.

If you are learning from scratch - then any introductory probability and statistics text will do the trick. You are looking for "hypothesis testing".

I take it you've seen this one:
http://en.wikipedia.org/wiki/Confidence_interval

How about something like this?
http://www.statisticshowto.com/articles/how-to-find-a-confidence-interval-for-a-sample/