Dr Taylor carried out a correlational study to investigate whether there was a relationship between daily caffeine intake (mg) and self-reported anxiety rating (on a scale of 1 to 10).
The results from Dr Taylor's investigation are shown in Table 1.
Complete Table 1 and calculate the Spearman's rank correlation coefficient for Dr Taylor's investigation.
Table 1: Daily caffeine intake and anxiety ratings
| Daily caffeine intake (mg) | Rank 1 | Self-reported anxiety rating | Rank 2 | ddd | d2d^2d2 |
|---|---|---|---|---|---|
| 200 | 4.5 | 4 | 3 | ||
| 100 | 2 | 2 | 1 | ||
| 200 | 4.5 | 8 | 6 | ||
| 300 | 6 | 7 | 5 | ||
| 50 | 1 | 3 | 2 | ||
| 400 | 7 | 9 | 7 | ||
| 150 | 3 | 5 | 4 | ||
| Total: | ∑d2=\sum d^2 =∑d2= |
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.