A sports scientist conducted a study on the effect of a 4-week high-altitude training camp on the anaerobic threshold of runners. They used a repeated measures design with 18 competitive runners. To analyze the difference in anaerobic threshold (measured in ml/kg/min\text{ml/kg/min}ml/kg/min) before and after the camp, they used a Wilcoxon Signed-Ranks test.
One runner's anaerobic threshold remained completely unchanged (difference = 0) and their data was omitted from the analysis, leaving N=17N = 17N=17.
The researcher proposed a directional hypothesis, predicting that the anaerobic threshold would increase after the training camp. Therefore, a one-tailed test was conducted at the 0.05 (5%) level of significance.
Using the table of critical values below, state the critical value for this test and explain how you located it.
| NNN | One-tailed, p≤0.05p \le 0.05p≤0.05 | Two-tailed, p≤0.05p \le 0.05p≤0.05 |
|---|---|---|
| 11 | 13 | 10 |
| 12 | 17 | 13 |
| 13 | 21 | 17 |
| 14 | 25 | 21 |
| 15 | 30 | 25 |
| 16 | 35 | 29 |
| 17 | 41 | 34 |
| 18 | 47 | 40 |
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.