BRAINCAKERandom Sampling with Quadrats
Random sampling means every part of the study area has an equal chance of being sampled. It is used to avoid sampling bias, for example choosing quadrat positions that look interesting or are easy to reach. It is most suitable when the area looks fairly uniform, or when comparing two different areas, such as a grazed and an ungrazed field.
Method
1. Lay out two long tape measures at right angles along two edges of the study area, to form the axes of a grid.
2. Use a random number generator to produce a pair of numbers.
3. Use these as coordinates, for example (7, 12) means 7 m along one tape and 12 m along the other, and place the quadrat there.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in Populations in Ecosystems
- Intraspecific Competition
- Interspecific Competition
- Predator-Prey Relationships
- Estimating Population Size with Quadrats
- Systematic Sampling along Transects
- Mark-Release-Recapture
- Assumptions of Mark-Release-Recapture
- Succession
All 20 lessons in Populations in Ecosystems · All AQA A-level Biology topics