An audiogram is a graph that shows the softest sounds a person can hear at different pitches or frequencies. … A hearing test helps to determine if someone has a hearing loss and the severity of the hearing loss. The results are recorded on a chart called an audiogram. The pure tone audiogram is a graph which shows the pitches (frequencies) across the top and the loudness (intensity) down the side. In general, the audiogram indicates how loud different sounds must be before they are first heard. The pure tone audiogram is filled out by an audiologist to indicate the degree of hearing loss. 

The audiogram of a person without hearing loss would show hearing at all frequencies between -10 to 26 dB HTL. All recordings on the audiogram greater than 26 dB HTL represent a hearing loss at that frequency.

More information can be found here: