Ecologists conducted a survey to investigate whether there is an association between the woodland zone and the nesting tree preference of a specific bird species. They recorded the number of nests built in deciduous versus coniferous trees across four distinct woodland zones (Zone A, Zone B, Zone C, and Zone D). The observational data are summarised in the table below:
Table 1: Nest count by woodland zone and tree type
| Woodland Zone | Deciduous | Coniferous |
|---|---|---|
| Zone A | 25 | 15 |
| Zone B | 30 | 10 |
| Zone C | 12 | 18 |
| Zone D | 8 | 22 |
Using the extract of the table of critical values for the Chi-square (χ2\chi^2χ2) test presented below, find the critical value at the 1% probability level for the data collected in this study.
Extract of critical values for Chi-square (χ2\chi^2χ2) test:
| Degrees of freedom (df) | 0.5 | 0.05 | 0.01 |
|---|---|---|---|
| 1 | 0.455 | 3.841 | 6.635 |
| 2 | 1.386 | 5.991 | 9.210 |
| 3 | 2.366 | 7.815 | 11.345 |
| 4 | 3.357 | 9.488 | 13.277 |
| 5 | 4.351 | 11.070 | 15.086 |
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.