AASM Sleep Technologist Practice Test 2026 - Free Sleep Technologist Practice Questions and Study Guide

Frequency is the rate at which events occur within a set period of time. It describes how many times something happens per unit of time (for example, events per second, per minute, or per hour). This makes it the right term for “the number of events that occur within a particular period.”

Duration, on the other hand, is how long a single event lasts. Amplitude refers to the size or strength of the signal, and polarity indicates the direction of the waveform. Since the question is about how many events happen in a given time frame, frequency best captures that idea.