A researcher investigates variation in leaf length among all the trees of one species in a woodland. Two sampling methods are proposed.
| Sampling method | Number of trees | How the trees are selected |
|---|---|---|
| 1 | 25 | Random numbers are applied to a numbered map of all the trees in the woodland. |
| 2 | 80 | The trees nearest to a path through the woodland are selected. |
Evaluate the two sampling methods and suggest how the researcher should obtain a more representative sample.
96 exam-style questions on Edexcel GCSE Biology 3.4 Variation and the Human Genome Project, covering 3.4.1 Causes of variation, 3.4.2 Outcomes of the Human Genome Project, 3.4.3 Genetic variation within a population, and 3.4.4 Effects of genetic mutations on phenotype. Each one has a worked solution and a mark scheme showing where the marks go.