A sports scientist investigated the effectiveness of two different pre-workout hydration drinks on athletic performance.
In Protocol A, 12 athletes drank 500 ml of a high-electrolyte solution 30 minutes before completing a 400 m sprint. In Protocol B, 12 different athletes drank 500 ml of a simple carbohydrate solution 30 minutes before completing the same 400 m sprint.
The results are given in Table 1 below.
Table 1: Average improvement in 400 m sprint times (compared to their baseline personal bests)
| Protocol A (Electrolyte) | Protocol B (Carbohydrate) |
|---|---|
| -0.8 seconds | -1.4 seconds |
After the results were recorded, the researcher asked all 24 participants to detail their dietary intake and sleep duration over the preceding 24 hours.
Suggest one possible extraneous variable in this experiment.
689 exam-style questions on AQA A Level Psychology Scientific processes. Each one has a worked solution and a mark scheme showing where the marks go.