A scientist investigated how many aphids are dislodged when the leaves of one species of plant curl after being touched.
The scientist placed 10 aphids on one leaf of each plant. The leaf was touched and allowed to curl. The scientist recorded the number of aphids that fell from the leaf.
The table shows the results of a pilot investigation using three plants.
| Plant | Number of aphids that fell from the leaf |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
In the main investigation, the scientist tested 20 more plants of the same species under the same conditions and calculated a mean.
Use the pilot results to explain how the larger main investigation gives stronger evidence about the number of aphids dislodged by a curling leaf.
133 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.