Question:

Emma experimented to determine if an individual’s pulse would be affected by listening to different kinds of music. She hypothesized that a person’s pulse rate would change if they listen to different music types. All persons were listening to 7 different types of music for 30 seconds. The pulse of each person was taken right before the music and also after the seven 30-second intervals of music. So after the music sections were completed, their pulses were taken again. Based on her experiment, Emma came to the conclusion that an individual’s pulse rate was changing when they listened to different kinds of music. In Emma’s experiment, what component is missing?