Everyone that gets a hearing test always asks the same thing--"What do all these numbers mean?" There are plenty of educational aids, but many get too detailed or they don't empower the reader with enough real information.
This is the best pamphlet and graphic I have ever seen that concisely answers this question. This is also one of the best training videos I have ever seen regarding hazardous noise/noise-induced hearing loss. Great for a less boring training day.
There's plenty of other stuff on the internet, but I like these.