Conservation workers compared the numbers of sea lavender plants in two saltmarsh plots, P and R. Each plot has an area of 100 m2. In each plot, they placed a quadrat with an area of 0.5 m2 at five positions chosen using random coordinates, and counted the sea lavender plants in it.
| Quadrat | Number of sea lavender plants in plot P | Number of sea lavender plants in plot R |
|---|---|---|
| 1 | 6 | 3 |
| 2 | 9 | 2 |
| 3 | 4 | 5 |
| 4 | 7 | 1 |
| 5 | 9 | 4 |
Calculate the mean number of sea lavender plants per quadrat in each plot.
Estimate how many more sea lavender plants there are in plot P than in plot R.
Give one way the workers could make their estimates more reliable.
82 exam-style questions on Edexcel GCSE Biology 9.1 Ecosystems and interdependence, covering 9.1.1 Levels of organisation in ecosystems, 9.1.2 Abiotic and biotic factors, 9.1.3 Importance of interdependence, 9.1.4 Parasitism and mutualism, and 9.1.5 Determining number of organisms in an area. Each one has a worked solution and a mark scheme showing where the marks go.