My daughter did a hearing test. the left ear, pressure reading is 0dpa. is that normal? the right war pressure reading -4. what does these figures indicate?

A typical hearing test produces a graph called an audiogram showing our ability to hear at different frequencies that is plotted by marking the lowest volume a patient is able to hear tones played at different frequencies. Volume is measured in decibels or dba and with normal hearing, we will first hear the tones between 0 and 20 dba. Do you mean dba , not dpa? If not, any audiologists out there?