In civil engineering, the curing time of concrete is crucial for its structural integrity and durability. A materials engineer conducted a study to investigate the relationship between the curing time of a specific concrete mixture and its subsequent water permeability index. A sample of eight test blocks was prepared, with each block cured for a different number of days before its water permeability index was measured (on a scale of 0 to 100, where higher scores indicate greater water permeability, i.e., lower durability).
The results are shown in the table below:
| Sample | Curing time (days) | Water permeability index (0 to 100) |
|---|---|---|
| A | 3 | 78 |
| B | 28 | 12 |
| C | 7 | 55 |
| D | 14 | 34 |
| E | 1 | 92 |
| F | 21 | 22 |
| G | 5 | 64 |
| H | 10 | 45 |
After carrying out a product moment correlation coefficient (PMCC) test on the data above, the calculated correlation coefficient obtained was r=−0.95r = -0.95r=−0.95.
Explain what this calculated value means.
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.