On the hearing test you are put into a sound booth and wear a headset. Tones are then played in each ear in turn, at different pitch and reducing amplitude. I think those are the right terms.
It starts easily and you confidently press a button when you hear the tone. As it gets harder you then start to imagine the sound and start to press the button almost in desparation. You may imagine that the repetition interval is uniform and press the button when you think you hear a sound.
Mistakes and cheating do not work. The test is actually repeated and they look for consistency not an absolute. When your job does not depend on it and you are permitted to see as well as hear you would be astonished how accurate it is.
One last point. While the booth is soundproof it is necessarily air tight too. So remember the person following you and no beans for breakfast
