A marine biologist conducted a study into the relationship between the depth at which a specific species of coral grows and its maximum skeletal length. She recorded the maximum skeletal length and the collection depth for 10 specimens.
The raw data and the sequential ranks for both variables are shown in the table below.
| Specimen | Skeletal length (cm) | Collection depth (m) | Rank of Skeletal length | Rank of Collection depth |
|---|---|---|---|---|
| a | 38 | 25 | 7 | 7 |
| b | 25 | 8 | 4 | 2 |
| c | 18 | 18 | 2 | 4.5 |
| d | 41 | 30 | 8 | 8 |
| e | 29 | 18 | 5 | 4.5 |
| f | 14 | 5 | 1 | 1 |
| g | 32 | 12 | 6 | 3 |
| h | 21 | 22 | 3 | 6 |
| i | 45 | 35 | 9 | 9 |
| j | 50 | 42 | 10 | 10 |
Explain why the collection depth data for specimens (c) and (e) have both been given the rank of 4.5.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.