A cognitive psychologist investigated whether the tempo of background music influences perceived physiological arousal.
They conducted a repeated measures design experiment using two versions of the same instrumental track: one edited to have a fast tempo (140 BPM) and another edited to have a slow tempo (70 BPM). First, participants listened to the fast-tempo version and immediately rated their level of excitement on a scale of 1 ('extremely calm') to 20 ('extremely excited'). One week later, the same participants returned to listen to the slow-tempo version of the track and rated their excitement using the same scale.
The data collected is shown in the table below:
| Participant | Condition A (Fast tempo, 140 BPM) | Condition B (Slow tempo, 70 BPM) |
|---|---|---|
| 1 | 19 | 8 |
| 2 | 15 | 4 |
| 3 | 11 | 12 |
| 4 | 18 | 19 |
| 5 | 20 | 7 |
| 6 | 14 | 9 |
Outline one reason why the reliability of the data collected in this study could be low.
