A cognitive psychologist wanted to investigate whether there was a relationship between habitual sleep duration and executive functioning, measured via a Stroop color-word interference task.
An advertisement was posted on a popular online forum dedicated to sleep optimization, SomnoOptimise, asking for adults aged 18 to 35 to participate. Eight participants volunteered for the study. They tracked and reported their average sleep duration (in hours per night) over a one-week period and then completed a laboratory-based Stroop task (with a maximum executive function score of 50).
The results of the study are shown in Table 1 below.
| Participant | Sleep duration (hours) | Stroop task score /50 |
|---|---|---|
| A | 6.2 | 38 |
| B | 4.5 | 29 |
| C | 8.1 | 45 |
| D | 5.0 | 32 |
| E | 7.4 | 41 |
| F | 5.8 | 35 |
| G | 6.9 | 39 |
| H | 8.5 | 47 |
Explain one limitation of the sampling technique used for this investigation.
186 exam-style questions on Edexcel A Level Psychology Research methods and skills, covering Research methods and skills. Each one has a worked solution and a mark scheme showing where the marks go.