Researchers measure the highest frequency heard by groups of adults involved in stage rehearsals.
Some participants are regularly exposed to intense sound during rehearsals. The Table shows the mean results for three groups.
| Age in years | Regular exposure to intense rehearsal sound | Mean highest frequency heard in Hz\text{Hz}Hz |
|---|---|---|
| 20 | no | 19 20019\,20019200 |
| 50 | no | 13 20013\,20013200 |
| 20 | yes | 16 80016\,80016800 |
Describe what the results show about the effect of age and the effect of regular exposure to intense sound on the mean highest frequency heard.
Assume regular exposure changes the mean highest frequency heard by the same number of hertz at both ages.
Predict the mean highest frequency heard by 50-year-olds who are regularly exposed to intense sound.
A cue with a frequency of 12 000 Hz12\,000\ \text{Hz}12000 Hz is proposed for rehearsals. The cue must be within the mean hearing range of all participants, including regularly exposed 50-year-olds. Explain whether the data support using this cue. Use a numerical comparison in your answer.
The equipment can instead produce a sound with a frequency of 22 000 Hz22\,000\ \text{Hz}22000 Hz at a greater intensity than the proposed cue.
Explain, in terms of intensity and the response of structures in the ear at very high frequencies, why this would not make the sound more suitable as an audible cue.