A researcher surveys bilberry plants in a 200 m2 area of heathland using eight randomly positioned quadrats. Each quadrat has an area of 0.25 m2.
| Quadrat | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|
| Number of bilberry plants | 0 | 1 | 2 | 2 | 3 | 4 | 5 | 7 |
The researcher estimates the population by multiplying the mean number per quadrat by 200.
Which statement correctly describes how this affects the population estimate?
The mean is 2.5 plants per quadrat. The researcher's estimate is 500 plants, but the correct estimate is 2000 plants, so the estimate is too low.
The mean is 2.5 plants per quadrat. The researcher's estimate is 2000 plants, but the correct estimate is 500 plants, so the estimate is too high.
The mean is 3.0 plants per quadrat. The researcher's estimate is 2400 plants, but the correct estimate is 600 plants, so the estimate is too high.
The mean is 3.0 plants per quadrat. The researcher's estimate is 600 plants, but the correct estimate is 2400 plants, so the estimate is too low.
83 exam-style questions on AQA GCSE Biology 7.2 Organisation of an ecosystem, covering 7.2.1 Levels of organisation, 7.2.2 How materials are cycled, 7.2.3 Decomposition, and 7.2.4 Impact of environmental change (HT only). Each one has a worked solution and a mark scheme showing where the marks go.