, because the N2 stage is predominant (often making up more than 50 percent of a night’s sleep), normal, and an important aspect of sleep physiology, contai...

https://www.apple.com/jp/healthcare/docs/site/Estimating_Sleep_Stages_from_Apple_Watch_Sept_2023.pdf

and older. During the hearing test, tones are played across a range of frequencies from 250Hz to 8000Hz at various intensities. Hearing tests are typically ...

https://www.apple.com/jp/health/pdf/Hearing_Health_Features_on_AirPods_Pro_2_October_2024.pdf