Dr Aris and Dr Vance are investigating whether there is a relationship between a person's self-reported daily caffeine intake (mg) and their mean reaction time (ms) on a computerised attention task.
Table 2 shows the raw data from their investigation.
| Daily caffeine intake (mg) | Mean reaction time (ms) |
|---|---|
| 150 | 280 |
| 250 | 230 |
| 50 | 340 |
| 350 | 190 |
| 100 | 310 |
| 200 | 260 |
| 0 | 420 |
| 120 | 290 |
Table 2
The researchers used Spearman's rho to analyse their data.
State two reasons why Spearman's rho is an appropriate statistical test for this analysis.
638 exam-style questions on Edexcel A Level Psychology Methods. Each one has a worked solution and a mark scheme showing where the marks go.