Three researchers were asked to estimate the population size of a saltmarsh plant species (Salicornia europaea) in a mudflat using a quadrat. The diagram shows where each researcher placed their quadrats in the mudflat:
Which researcher would obtain the most reliable estimate? Give reasons for your answer.
State what is meant by the term population.
Five other researchers investigated the distribution of a lichen species (Xanthoria parietina) on a vertical stone wall. They placed a small quadrat (10 cm by 10 cm, divided into 100 squares of 1 cm by 1 cm) at the base of the wall (0 m) and then at 1-metre intervals along a vertical transect up to the top of the wall (4 m). The percentage cover was recorded based on how many of the 100 squares contained the lichen.
The table shows the results obtained:
| Researcher | 0 m | 1 m | 2 m | 3 m | 4 m |
|---|---|---|---|---|---|
| U | 12 | 32 | 48 | 65 | 81 |
| V | 16 | 37 | 52 | 62 | 85 |
| W | 11 | 34 | 46 | 12 | 78 |
| X | 14 | 38 | 51 | 68 | 84 |
| Y | 12 | 34 | 48 | 61 | 82 |
| Average | 13 | 35 | 49 | 64 | 82 |
One of the averages has been calculated by ignoring an anomalous result. Which researcher obtained the anomalous result?
The diagram below shows the quadrat used by one of the researchers at 2 m:
Which researcher obtained the results shown in this quadrat?